I just upgraded my Sony PSP to the new Firmware 2.70 and downloaded the free LocoRoco Game demo published by Sony in Japan today.

LocoRoco is a fun platform game with a singing ball bouncing through a colorful world. The ball is getting bigger by hitting certain flowers. You can split then again into single balls and get through different obstacles.
With the left and right buttons you can tilt the world to gain speed and jump over hills. See several screen-shots in our gallery.

I played the LocoRoco demo on the PSP now for just 10 min. It is easy to learn despite all text being in Japanese. The LocoRoco download is about 8MB.
To play the LocoRoco demo game, you have to first update to firmware 2.70. Then download the game demo from Sony here (click on the green button). Then transfer the file EBOOT.PBP (the file has the same name as a firmware update) in a new folder UCJS10041 under PSP/GAME folder on your Sony PSP.

Close the USB connection and select the memory stick under the game icon and the LocoRoco file will appear. Selecting it will launch the game. Click the Start button to start the game and start moving the ball around - have fun.