Multi Color Particle Smoke
Type "/33change" and a menu will drop down allowing you to choose 10 colors or turn the particles off.
You can also use voice commands on channel 33, as follows:
/33 on_off
/33 white
/33 black
/33 gray
/33 blue
/33 red
/33 green
/33 yellow
/33 cyan
/33 magenta
/33 rainbow