Ian from Dangerous Prototypes has made a high tech Multi Color Remote Controlled LED Pumpkin. It uses a remote control to change the inside glow color. Schematics and code are provided so you can make your own.

Via: HG Forum.

"It uses a minimal PIC 18F2550 circuit that decodes the remote control signals and drives a ShiftBrite color changing LED module. The F2550 is a USB PIC with a USB bootloader, so it’s technically a USB upgradable pumpkin too. The color changing LED is a ShiftBrite module from Macetech.com. It’s driven by three PIC pins and powered by a 5volt supply."