Railguns!

this is a video of a navy test
i think that this one probably has a muzzle velocity of about 16000 feet per second
basically the idea is that massive amounts of electricity are used to create a magnetic field which propels the object forward
i am currently working on making my own (smaller of course)
if you would like to also you can find instructions here
http://www.instructables.com/id/How-to-make-a-RAILGUN!/