Bright Lights…Awesome Sounds…
You have to play Lumines.
Nothing can really describe just how awesome, or synaesthetic the game really is. Tetsuya Mizuguchi really outdid himself again with Lumines. It attacks the senses and feeds on them as you're playing. I can't say enough good things about it…it's just amazing. If you have a PSP, or even if you don't have a PSP, you need to at least try out Lumines, you'd be doing yourself a disservice as a gamer otherwise.
I could go into deeper detail on it, but I'd more than likely completely lose everyone as I do it, so I'll save you the time and your attention span. Anyways, I also got a chance to try out Metal Gear Ac!d, and it's really not too bad. The card game mechanism that the gameplay is centered on is a little difficult to get used to, but by the time you've gone through the first three situations, you'll have a pretty good feel for it. The game looks great, and next to Ridge Racers, it's probably the best-looking PSP game at launch. If you're a MGS nut, you're probably going to have to play it. And even if you're not, it's not a bad game to try out for a little while if you're bored.