I bought a bike computer. It's an Avocet 45tt. It was about $50.
It was a royal pain to install on my bike. First I tried to install it on the rear wheel. After fussing with it for a long time I concluded that it was impossible given the way my bike is designed, so I moved it to the front wheel. That turned out to be possible, although still difficult.
The final problem was that the wire from the pickup to the display was just barely long enough. There's not even an inch of slack. Come to think about it, I can't see how it could be long enough to go all the way to the back wheel of any bike at all.
It turned out that even though this model supports cadence (speed turning the crank, in rpm) it doesn't come with the proper sensor for it. I guess I will have to go back and buy that separately. I am kind of upset because the guy at the shop told me that it came with everything needed and I had explicitly said that I wanted cadence measurement.
Screwing around with trying to mount it every which way, I managed to use up all of the cable ties that came with it, so I went to Fry's to buy some more, with the wire held in place with tape in the meantime. I found out that it's 1.96 miles from my apartment to Fry's.
Now I also know that it's a 9.11 mile round-trip from my apartment to the San Antonio shopping center and back. My average speed along the way was 12.93 mph (it would have been faster except for the stop signs placed every two blocks or so along the way), and my maximum speed was 24.4 mph (kind of low I guess, but I have a cheap, heavy mountain bike).
In other news, I've been reading this book that examines the historicity of King Arthur and the surrounding legends. It's very exciting because the evidence all points toward King Arthur, Queen Guinevere, Lancelot, and so on actually having existed in the 6th century A.D., although in ways and places that are quite different from the ones that we normally hear about. I wonder if anyone has ever written a version of the King Arthur legends based on these historical findings? I am half-tempted to do wider and more detailed reading on the topic, then try my own hand at it. (The book is King Arthur by Norma Lorre Goodrich, ISBN 0-06-097182-7, published 1986.)
I think I'm going to go out and bike some more now.