Our good friends at Massively beat us to the punch on this one: as seen on Gabe's (of Penny Arcade) little blurb yesterday, Gallery Nucleus in Alhambra, California is holding an "Art of Blizzard" Benefit Show for Child's Play, the charity started by Penny Arcade to buy and donate videogames to children in hospital. Additionally, Blizzard artists and developers will be in attendance at the event, and Upper Deck will be there demo-ing the WoW TCG (which is probably where some of the art comes from) as well. And the art is going to be from all of Blizzard's different games, not just World of Warcraft.
The PDF press release has more info, and admission is free to the public. I don't think any of our correspondents are in the area, but if you're around and get to go, be sure to take pictures and send them along to us. It definitely sounds like a fun event, and it's always great when developers put their time and work in to help out a worthy charity.