Lylatitude has updated his homebrew game for the PSP, In The Air, to Build 2060115. In The Air is a re-written plane shooting game, originally on Windows. You need to rotate your PSP 90 degrees to play. The source code is released too. Message from the author:

With the help of Plain Boiled Water, the administrator of PSP development forum in PSPChina, I've cleared those 2 bugs in the ITA. The Exception will occur when using "mikmodlib" incorrectly. The correct method is: play the music after stopping and freeing the music. Now the game runs OK and exit without any exception.