A blog run by DroidFreak, AKA Mark Dykstra. A mixture of all sorts of cool stuff, from Rubiks cube solutions to Lego robots.
Semi-Automatic Shell-Ejecting Lego Shotgun
In other words: Epically awesome Lego gun. The only problem it has is that it has fairly low range and power, but it is great for close range use. It fires 6 shots of 3 bullets (3-unit Lego beams) each. It shoots every time you pull the trigger and it ejects a "shell" with each shot as well.