This shot was taken in a pitch black room with only the lava lamp as a light source. The colour of the lava lamp is purple (left). The walls are a very light cream colour, not quite fully white.
Here are specific details of both images:
EOS 300D w/ EFS 18-55mm
Left: Purple (actual)
White Balance: Tungsten
Right: Red (warm)
White Balance: Fluorescent
Perhaps what I'll do tonight is move the lava lamp away from the wall and produce a flat picture of the purple and red, then use that as my custom WB to take a regular indoor/outdoor shot. Or do you prefer we not use such colour extremities? Are you looking for the more common WB errors?