Building a budget fixed gear bicycle

Fixed gear bikes ("fixies") were rarities on the road a few years ago; now (2010) I see a few every day. To satisfy my curiosity about riding a fixie without spending a lot of money, I built one mostly from spare or scavenged parts. Being a fixed gear newbie, I needed a lot of advice.

The project evolved into a quirky experiment, trying to keep costs down by avoiding expensive new bicycle parts. Here's how it went.