Before the Eloader the only way of playing homebrew on Consoles up to v2.6 and infact beyond that is the PSP Adventure maker, well there has been a load of games that even i havent posted about and one looks like a real killer release, heres the games and any info:
T'alvi
T'alvi is a first-person point-and-click adventure game in the style of Myst(*). It features full-resolution pre-rendered pictures and animations. It was also the first full-length game ever released as a free download for legal 2.x PSP's.
Kill The Stickman
Bounce rocks to kill the Stickman