I saw green (and purple) that night.

This was difficult to achieve on my own, but could easily be done with help.

A rough guide to what I did.

Total darkness, held the cam with feet aimed at my face, placed 2 coloured gels in the flash, one just in the gel slot, other fully in. Held open the shutter, manually set the flash off to the right of me, removed one gel and pushed other in. (shutter still open) Moved slightly forward and did a rarrr face, manually set of the flash on my left side. Released the shutter.