Sorry if anyone has posted this but its not more than a week old and it still blows my mind everytime I watch it.

This is a new weapon technology being developed and even though it is still in its early stages, its amazing to say the least.

http://www.delaywork.net/index.php?params=game/286/Vortex-Cannon/

Not sure how that could have much practicality in combat, but it sure looks cool.

weak as fuck on the bricks.

^This :D!

Wow, it only just managed to knock over an un-mortared brick wall, holy shit!

two words: Intimidation Factor... Combat scenario thats looking you in the face? FUUUCKK THAAATTT lol

Imagine using that thing in snowball fights.

Lol, when I was in Venturers (NZ scouts except for 17-19 year olds and way less structured/campy than the stereotype) we made a cannon not unlike this. Except it was filled manually from a welding system, was made out of two metal pipes welded together, was handheld and fired by a BBQ sparker attached to a spark plug.
Fired coke bottles filled with oxy-acetylene and on-impact igniters made from matches and gaffer tape a few hundred meters. Had to stuff the tube with newspaper otherwise the bottles would be ripped to shreds inside the cannon. Now that's something practical, would work as a grenade launcher or a mortar quite proficiently if you wanted to modify it to remove the gas reload. This is just a glorified hairdryer.