Si:
Someone really should be collecting some of these great but unusual Arduino project ideas.'A chameleon mister' - every home should have one
Could you adapt one of those PIR activated smell squirting things have started to infest our homes (an Airwick Freshmatic I believe)?
Chameleons are... cold blooded, I guess they have no problem fooling a PIR sensor.
I do agree this one should be included should our kids build an Arduino-museum one day. 