I haven't seen ANYONE bring this up yet -- the game "Loco Roco" from an internal Sony team is being demoed in the back of the PSP area, and it's pretty frickin dope. You play this blob thing and tilt the playfield with the R and L buttons, and can make the blob thing jump by pressing and releasing L+R. Very clean graphics, really slick dynamics on your blob-sperm-looking dude, very stylish little game. I think you can download the full demo to your PSP, too.
Anyhoo.
Anyhoo.