Kyle Luge comes up with his first full blown Playstation Portable homebrew game named TimeCube. It features multiplayer adhoc competitive play and single player modes! Read more about TimeCube v2.0 (PSP Game)
Dave Gnukem is a 2D scrolling platform shoot-em-up. It is very similar to and inspired by Duke Nukem 1. The initial port was done by deniska in 2006. It seems a user named lukensteinz has done a little bit of code cleaning, while also getting it to work on newer firmwares, Read more about Dave Gnukem (24-06-2011) (PSP Game Port)
Another CFW for the PSP is around, this one claims to be "most compatible Aftermarket Custom Firmware". Please be aware that modifying your Firmware might brick your PSP and will break you warranty! Read more about PRO-B7 Custom Firmware (PSP OS)