Check this out, I just installed it:
Ok, so it's a bicycle speedometer. It cost $32 and was pretty easy to install. Instead of using the normal magnet that clips onto your bicycle spoke, I bought one of these:
http://www.trailtech.net/B011-8.html
It's a bolt with a magnet in the head and it replaces one of your brake rotor bolts so you don't have to clip, glue, or otherwise rig a magnet onto something.
To set it up, I simply had to figure out the diameter of my front tire. I did this by standing the bike upright, and measuring from the ground to the center of my front axle to get the radius of the tire and then multiplied that number x2 to get the diameter. Then, I referenced the instructions of the speedo and found what value to assign for a 22" tire. I'm going to check it against a friend's car tomorrow, but after a test ride it seems to be pretty close. I had it up to 70mph, so I know it at least registers that fast, probably faster.
It has many cool features, I'm sure you bike riders are familiar. Top speed, avg speed, ride time, clock, multiple trip meters, odometer, etc. The only gripe I have is that I didn't think to get a backlit model.
It's pretty cool and probably more accurate than the stock unit, with more features, and ultra lightweight!
Linear Mode
