I just saw Clint Eastwood's Gran Torino for the first time the other day. This DIY paintball turret would have made the ending... different.
At 38 balls per second, this turret would have easily displaced any Asian street gang member who stood in Clint's way, or on his lawn.
As a DIY project, the same could be said of you and your lawn, should you choose to invest the time to build one. Careful though, the prototype you see here took two years to build. [Inventgeek via Hackaday]