What would you do spectacular with it that if it was destroyed or rendered useless it wouldn't matter? What kind of shots, setup, subjects? I have a junk Quantaray 70-300 lens that I have been trying to figure out what to do with for a while now. Whatever it is, as long as it doesn't harm the camera body itself, I'm game.
The fish tank one is an idea from a friend of a friend who has an old dead Pentax film body and lens withou glass that his fish swim in and out of. No pictures of it but I'm working on it
1) Coffee cup, like DigitalRev did with a 300 f/4L lens.
2) Pencil & pen holder
3) Kaleidoscope - smash a couple of internal elements and you're good to go
4) Door stop
go to a very public area, knock it off of something and have it smash onto the sidewalk, pavement, etc. and then run around shrieking hysterically "THe horror! The HORROR! Oh mY god I broke it! I broke it! For the love of god nooooooooooo! ohhhhhhhhhhhhh noooooooooooooooooooo! my god!!!!! the horror!!!!! ohhhhhh!!" for five minutes. Then pick the shards up and very calmly and collectedly walk away as if nothing had happened.
Firecrackers in the caps on the ends and some high speed photos... Might get a few pops before it's completely toast. EDIT: On second thoughts on one end only and see if you can recreate a saturn5 launch.
Guns/bullets have been way over done but how about a william tell deal for it? Lens sitting on an apple with arrow right thru the glass?
Take a wheel off a skateboard and bolt it on and see if it will roll with the focus ring as a wheel?