Sony has been busy releasing a couple of new demos for PSP owners. Yesterday a special Halloween LocoRoco demo was released, as was a demo of Namco's MotoGP in which you get to try out the Valencia circuit. Both demos can be found over on the Official PSP Store.
Both demos require firmware version 2.71 or later, and speaking of firmware, version 2.82 has also just been released and offers a bunch of new security stuff. You'll find the PSP firmware update over on YourPSP.com.