Jim Lee did this on Saturday towards the end of the show and they auctioned it off on Sunday afternoon out by Artist's Alley. The thing was though, NO ONE knew about.
No one even knew he was over there drawing it, let alone when it was going up for auction.
On Sunday, they just made a brief announcement over the PA system that the art auction was beginning and I got over there at about half an hour into it, right as the piece before it was ending.
There were maybe thirty people around, who looked just as happy to be sitting down as they were there for the art. IIRC, the opening bid was $400 and it was even a struggle to hit a thousand.
The bidding almost came to a halt somewhere around $700, but the auctioneer kept calling for bids, knowing it was worth more than that.
Finally, they got over that hump and some more people started milling around. The bidding improved a bit and finally topped-out at $1500.
For more in-progress photos, please check out:
http://groups.msn.com/artofjimlee