Sony has released quite a few downloadable demos of games lately, like Loco Roco, Ape Escape Academy 2 and Ridge Racers 2, which can downloaded and saved on the Memory Stick.

You can find links to most demos on the PSP Fanboy site, along with instructions on where to save them.

If you are browsing via the PSP there is a nice page to make it easier to download them directly, just go to net4psp.com and click on PSP Demo Downloads.

Several of the newer demos require that you run firmware v2.80 or later, which is unfortunate, but there are demos available for older firmware versions as well so you don't have to break the homebrew abilities.

In firmware v2.80 there is an added Flash player for the PSP and there are a few Flash based games out there wich can be downloaded and played. You can find a package of arcade games on PSP 411.