SUPERRED!

Hacked the front off an old digital camera and replaced the infrared filter on the CCD (the sensor) with a piece of floppy disc.

 

Floppy disc does the opposite, blocking visible light and passing infared.

Its not perfect infared (does not show infared released by heat) and its blurrier than the camera used to be, but it looks nice.

By changing the lighting settings on the camera you can get it red or purple.