In terms of things that you do in your spare time, this one has falls into the 'go big or go home' category. And maybe the mad genius/sociopath category.

Jason Bell built this human catapult in his own garage for reasons unknown (other than why the hell not), and after demonstrating its success with throwing people in lakes (fun) he upped the ante and started flinging people off bridges (not so fun). But yay DIY science?

Via YouTube