There are a lot of blogs out here in the Blogosphere. Some, like mine, veer off in every direction, while others focus like a laser on one subject, or even a specific project. The project covered in the Railgun Blog is the design and construction of a homemade electromagnetic railgun.
Unlike a conventional gun powered by chemical explosives, the only limit to the velocity a railgun projectile can obtain is electrical inductance in the rails - too much juice and the electricity will arc and vaporize the rails - so enormous speeds can be obtained. Unfortunately there is an equal and opposite reaction on the gun, as well as a good deal of heating from the large currents and friction. As a result, a railgun takes a lot of punishment and must be serviced after just one shot.
In spite of the fact that a railgun is, oh...let's say impractical, this guy is having a lot of fun with it, as you can tell by his emphatic yells of "OH YEAH!" on videos of his test firings. Ya gotta love it!