Freedom Unite my beloved.

A friend hacked his PSP and let me borrow it for a week to try out "this new Monster Hunter game he found" when I was and it single-handedly made me go out and buy a used PSP to do the same. I put so many hundreds of hours into that game, even soloed the guild double-Tigrex mission (scaled for a party of players).

There's a few emulators for older systems that can run on PSP hardware, too -- it's how I first played the NES Castlevania and Megaman games. Looks like it can do up to about the SNES/Genesis era fairly well?