Was able to get a used G&W Gallery 4 on ebay for about 15 dollars including shipping a couple of weeks ago.
It's electronic old-school/new-school crack, I tell you. Old and new G&W games are on here, and they're both fun. I think there's decent replay value and challenge, because in order to open new games, you have to earn stars (non-accumulative, btw) by getting high scores above 100 points.
My favorite new school game is Chef; a little bit of Iron Chef and Emeril mixed in with Yoshi ;). The hardest game right now is the old-school Chef; it's Ed Sullivan-plate spinning craziness at its best.
US PlayStation Store for PSP - Savage Moon: The Hera Campaign ($9.99) - Aedis Eclipse ($9.99) - Me & My Katamari ($19.99) - Football Manager Handheld 2010 ($23.99) PSP Minis - Bowling 3D ($4.99) Game Demos (free) - Holy Invasion of Privacy Badman!