Thanks (maybe?) to Datel you can play WipEout Pure and Tomb Raider: Anniversary with tilt control. Just purchase a TiltFX from their online store for $19.99, plug it into your PSP’s remote jack, and you’re ready to go.
Datel also created Custom FX profiles which alter physics so you can do ridiculously high jumps and float back to ground in games like Grand Theft Auto: Vice City Stories. Looks gimmicky, but it might be fun to use with LocoRoco, which seems to be made for this device.