God Bless America Again (With Billy Preston, Slash A.O. aka The American Rebels)

Compilation album: Ray Charles Sings for America, Rhino/WEA, 3 September 2002.
[After the album release, the song was remixed for radio DJs; see below].

The weeks after the 9/11 attack the American airwaves were filled with patriotic songs. Ray's America The Beautiful was probably the song that was most frequently played.
A year later Rhino/WEA released a compiler, Ray Charles Sings for America, spanning the Ray Charles Songbook from 1960 to 1997. All the songs' lyrics were especially meaningful in the context of the commemoration.
The 20th track, God Bless America Again, was newly produced for this album.
Producer Terry Howard revealed how the song came about at the occasion of Ray's and his endorsement of Sonar 2.0 studio equipment (source here):

The crew contributing to the track posed as
"Ray Charles and the American Rebels" for the photo
above. From left to right: Ray Charles, Rosemary
Butler, Billy Preston, Slash, Magic Kramer, Craig
Eastman, Jimmy Powers, and Scott Lombardi.

"We were all really affected by the tragic events of September 11th. Everyone involved with this project wanted to do something to help out but we were not sure what. The seed for the idea started when I saw Congress get together to sing God Bless America to rally our nation. This was the group that separated church and state in the first place, and they chose to sing this song rather than the National Anthem. I was really moved. I thought that maybe it might be a song that we could do to raise some money to help the victims.
I did some research on the internet and found that just about everyone had recorded God Bless America already, over 1000 people in fact. While I was looking, I found a single instance of God Bless America Again that was recorded by Loretta Lynne and Conway Twitty in the 1960s. It took a while, but I tracked down the song (none of the Country stations in the LA area had a copy to play). When I heard the track I knew there was something very special about it, and when I played it for Ray he said "We've got to do that song".
I started making some calls and just about everyone I contacted said they wanted to get involved. The opportunity to work with Ray is usually enough to get someone involved in a project, and the fact that this was for a good cause made it even better."

In another interview initiated by Sonar (source here), Howard  outlined the technical details of their recording process:

"After we had most of the backing tracks recorded, but before Ray cut his vocal, he decided that the drums needed a different arrangement. We used Sonar's Remove Silence feature to slice the drums into individual hits. Ray and I then rearranged the drums until they had it the way he was looking for. I then had Scott Lombardi, the drummer on the track, learn and recut the parts. We also used Sonar to slide the bass line to lock up with the new drum tracks in a few places. [...]
We always back up our tapes. At one point during the process I was backing up a number of tracks from one tape to another and we had an equipment malfunction that resulted in 4 seconds of original tracks that had not been backed up being damaged beyond repair. Luckily I already had 80 percent of the song within Sonar, and I found sections of audio that matched the lost perfomances, then blend them into the gap caused by the damaged tape. [...]
After finally hearing the single played over the radio I've decided on a few tweaks I'd like to make to the mix. I'm in the process of remixing the track now. When I'm finished I'll export a hi-res MP3 of the new mix that we can service to program directors across the country."

Who knows more about that remix?

Ray Charles In Yamaha Millennium Concert (2000)

The 2000 Yamaha Millennium Concert was a tribute to Michael McDonald's career. Acts included Ray Charles ("giving his Yamaha keyboard a workout on I Don't Need No Doctor"; see review here), Patti LaBelle, Kenny Loggins, Alan Parsons, Brian Wilson and the Doobie Brothers. The show and its video taping took place on 4 February 2000 (but I've never seen a release of the video, BS).

Charles was active in more Yamaha-sponsored events, such as the Sir Charles Blues Lab Blues Off 2002 for young songwriters, where Ray also invited Slash as a teacher (next photo, 6th from left). You can listen to a radio reportage here. 

On 17 January 2003 Ray was one of many performing guests at The 2003 NAMM Concert Honoring Sir Elton John (next photo), singing the duet version of Sorry Seems To Be the Hardest Word with Elton. Also read this, this and this.

In June 2003 Corey Levitan wrote (here and here) about another occasion at RPM's, this time with the South Central's Washington Preparatory High School jazz band, winner of a charity bands battle, whose prize was a recording session with Charles. The only thing they'd been told was the song they were performing: Let The Good Times Roll.

Ray, Slash, Billy a.o.

That same day former Guns N' Roses guitarist Slash payed a visit to RPM, also to jam with Ray. The former Guns N' Roses members had just reunited, without Axl Rose, and were auditioning new frontmen. In addition to Sorum, Duff McKagan joined Slash in the studio this day. They came psyched to jam with Charles, too. (Unfortunately, there wouldn't be time for that).

Under recording engineer Terry Howard's direction, the students launched into the first of 10 run-throughs. Ever the rock star, Slash plugged in a Gibson Les Paul and lighted up a cigarette, and "drips his trademark blues juice over the backbeat".

When Charles dropped in, Levitan had a brief interview with him. [links to sources broken]

"Seated behind a Braille laptop, the superstar is backdropped by about 75 gold records and keys to most major American cities," Levitan writes. "He grabs the air for a handshake. He finds a forearm, then slides his way down with a smile."

"I think there's less opportunity today," Charles answers the first question. "I came up with good musicians, and they would have jam sessions. And if you were good, they'd let you sit in. They had places where musicians could just go and just play music. I don't see that today. Matter of fact, I don't think I would have made it if I came up today.

""OK, let's go," Charles says. [...]  "Don't be shy," he says, smiling. He listens intently as drummer Michael Roundtree, 17, kick-starts the shuffle beat that causes good times to roll again. Once more, Dennis gives 110 percent.

After it's through, Charles doesn't congratulate the students. He corrects them. "You're C-natural," he tells Luebrun and the other horn players. "The first one is B-natural, the second is C-natural. Then you play your F-sharp."

Charles doesn't like horn sections playing in unison, so he offers suggestions that slowly bring harmonic color into the room.

Then he begins scat-singing less specific direction, such as "more dee-dee-ba, dee-da-ba." Finally, he lurches into his trademark piano bounce and joins in. The kids are now actually jamming with Ray Charles. After about an hour, the Washington Preparatory High School jazz band has cut a record worthy of the best blues compilation albums.

Corey finished his story with the promise that the recording would be placed on the Blueslab.org website, but that's presently not functioning...

Two other Blueslab activities were announced, but - to my knowledge - never happened:

• In December 2002 Music Connection wrote that "Roger Waters, Sinbad, Queen guitarist Brian May, Ray Charles, and producers Glen Ballard and Erick Sermon have joined the Blues Lab team to orchestrate an all-star televised concert to be executive produced by filmmaker John Landis (Blues Brothers, Thriller). The concert will pay tribute to the blues and launch an international blues education initiative for kids, similar to the Boy Scouts or Girl Scouts. The event will be recorded to create a 12-song curriculum album which enables kids and adults to teach themselves the blues."
• On 24 September 2003 a Pink Floyd fan picked up that "On Tuesday this week, his birthday, Ray Charles took the occasion to announce his own gift to the world, a national songwriting contest for kids to be sponsored by The Blues Lab and Comcast, which kicks off September 30th. The final song selection committee spans across the oceans and seven decades of music, from the birth of Soul, to British Progressive Rock, to Country, to American Rock Funk, to contemporary Hip Hop and R'n'B, all of the artists on the panel have their roots in the Blues, and are well qualified for the task of picking five great new Blues Lab standards. They are: Ray Charles - keyboard, sax player, songwriter and genius of soul; Flea - bass player and songwriter for The Red Hot Chili Peppers; Alicia Keys - keyboard player and songwriter; Willie Nelson - guitar, harmonica player, songwriter and country music legend; Sir Charles - keyboard player, songwriter, and founder of the Sir Charles Blues Lab; Willie Hill - saxophone player and President of the Music Educator's National Conference; and the one and only Roger Waters!"