If you don't have it, get it. Best tripping/stoned gave ever. I'm not much on video games, but Katamari and Soul Caliber are amazing. Katamari: You have been employed by the Ruler of the Cosmos to roll a Katamari (ball o' shit) of everything. Just play it.
By far one the best game to play stoned. Theres supposed to be a second one coming out sometime soon.
Seriously, Karamari is an awsome stoned game! i love it.. rolling stuff.. ahhh such good ideas from japan!