Canon at one point sold these little 300mm/400mm Image Stabilized Lens Replica Keychain LED Flashlights which quickly sold out. I managed to track one down for my random collection. The Flashlight is only about 2" long and 1" wide with a single LED bulb. There are no on/off buttons to manage the flashlight. To turn on/off the flashlight you'll need to turn the lens body which seats the battery connection inside. On the side of the lens is the keyring which includes a Canon charm (opposite side stays 'Image Stabilized').
The little item is now being represented on my backpack.
So random, but a very cool gift idea if you can track 'em down. There's only one spot to find them on eBay (click here)
Canon Lens Replica KeyChain LED FlashLight