So I asked singer and guitarist Drew Holloway for more details.
"It was a week-long camp but the three of us did a fair share of tracking in the weeks before and after camp. Jack [Forman, bass & piano] did the massive job of mixing the cd which we then had professionally mastered.
The camp was made up of over 80 kids. 30 of the kids were 3-6 years old and spent the bulk of the day in a separate camp on site. In the morning, however, those children joined the other group, 6-11 years old, for a "gig" [group sing-along] and some big group recording [like in "Aquarium" and "Fred"].
Each afternoon consisted of three sessions [songwriting, recording, and artwork]. We divided the 50 kids into three groups [land, water, and air] and they rotated through each activity.
I worked with the songwriting group. For the most part I was the Elton John and they were the Bernie Taupins. Sometimes small musical snippets made their ways into songs ["Squirrels" was based on a camper-generated bass line]. The kids worked mostly in pairs and small groups to draw and write stories. When it worked we combined ideas like in "Chicken" and other times we voted for favorites "Pet Shark."
Daron [Henry, drums] led the art contigent. Kids created animal-letter typography and foot-high self-portraits. The portraits were used in an installation that later, through the magic of photoshop, became the cover.
Jack was the captain of the recording booth. He taught the kids about basic engineering and multi-track recording [We used protools]. In the studio, campers laid down vocal and percussion tracks. Their favorite part was always listening back.
We ended the day by singing some songs and doing a guitar solo overdub in front of the whole group. What a blast."
Holloway also reports that they'll be doing two weeks of the camp this year, maybe with a video/DVD component.
Others have wondered in the comments, and I agree -- why don't more artists try this? You'd certainly have to have a certain patience to deal with dozens of elementary school students, but a lot of kids' musicians have at least some familiarity with teaching kids.
A (summer) school of rock (or folk or pop or whatever) would be pretty awesome for a lot of kids.