A few years ago, when I was first starting out, I modeled a violin. Lately, I've thought it would be a great idea to revamp the violin into a weapon. I chopped off the majority of the model, and made a crossbow put together from junk you'd find at a mall. A music store, hardware store, and furniture store are all you need to create this not-for-long-term-use weapon!
The limbs of the crossbow are from a plexiglas stick.