If you're into paintball, here's a great project for you. This site shows you how to make an air cannon, which is perfect to load up with paintballs for the ultimate paintball battlefield weapon. Other suggested uses from the site are loading it with confetti or lofting chemical glow sticks on parachutes for a safe (safer than gunpowder based fireworks anyway) fireworks show.
Here's a cool Popular Science article that shows you how to make ice cream using liquid nitrogen. After you have the ingredients mixed, the liquid nitrogen turns it into ice cream in only 30 seconds. According to the author, this is the best ice cream he's ever tasted due to the rapid freezing process which minimizes ice creams graininess.
The CPL regularly hosts tournaments with prizes of up to $100K. Not too shabby for playing games. There was an article on Kuro5hin not too long ago describing the downsides of professional gaming, so it still may have a ways to go. Also an article on BBC talking about Korea being the place to be for professional gaming these days.
Here's a link to a very cool motorcycle/computer mod. This guy added a Unix machine to his bike. Might be wondering why someone would do this, and he's got some pretty good answers. Right now he can record videos with his helmet cam, and eventually wants to log his riding using GPS.
By way of this Slashdot article
Ever wanted to make your own astronomical images like those from the Hubble? Take a look at this site that provides instructions and the software (Photoshop Plugin) to create your own images from the raw data from the Hubble Space Telescope. While there, take a look at some of the beautiful images in their user's gallery.
Sam's Laser FAQ provides all the information you need to get started with lasers. The site is a little tricky to at first to find the info you're looking for, until you stumble upon the Expanded Table of Contents. The site is very text heavy (many of the diagrams and schematics are done in ASCII), but if you've been wanting to build your own laser, this is the place to start.
Engadget has an interesting project, on how can you turn your iPods into a universal remote control. Which can be used to control all your home electronic equipment, or just about anything that uses a remote control, for example in our place we have our iPod controlling our TV, DVD Player, Direct TV, Ultimate TV PVR, Media Center PC, Xbox, XM Satellite Radio, Roomba and a few other random things like a Robot.
Very basic instructions on how to create a very simple mini levitating (maglev) train. A fairly simple project that would also be fun for the kids.
Build an inexpensive seismometer using instructions and links from this site. The site mainly has descriptions of his projects without going into great detail regarding how to build a seismometer, however the links and the resources listed give you everything you need to build one yourself.