My brother had a dart board in his room (which wasn't really big enough for a dart board, but he had a big noticeboard thing that prevented wayward darts from taking chunks out of the wall). I was banned from playing darts after one rebounded off the wire bit and landed in his (bare, as was his habit) foot.
Nevertheless, one bored afternoon watching progress bars on his computer[1] found me fiddling with assorted cardboard and stationery, and without really paying attention I fashioned a kind of elastic-band-powered dart crossbow. What it lacked in accuracy it made up for in muzzle velocity, as we discovered when the errant dart thoroughly impaled his teenage boy standard-issue can of Lynx Nevada. The resulting shock and awe meant that neither of us were quick-thinking enough to lob it out of the window before the contents had finished escaping, and the upstairs of the house smelled like a PE department for weeks.
The moral of this and other stories, is that I shouldn't be allowed to play with projectile weapons.
[1] Which reminds me, it being the post-Thatcher era, he had a particularly smug looking photo of Bill Gates on the dartboard for a while.