Here is a big project I made a while back.
Some tome ago I played around with some Minecraft portable programs, and many of them were not as Portable as they said. The program would save the Worlds on the Harddisk and not on the USB also need Java installed on the computer, then I found one that had Java on the USB and did not require Java installed on a computer. But it still saved the worlds you made on the HD. So I looked over the code and tweaked here and there, so now you can have Minecraft with you were ever you go. It runs Java from the USB and Minecraft plus it saves the Worlds onto the USB also.
Lets just drive into it shall we.