I thought this was kind of neat. An http proxy is a useful tool to have, there are many types for many different purposes. It's a program that you can put between a client and a web server. See the wiki article for all the common uses for a proxy. Anyway, after playing with these for a couple of days I had some needs at work that it seemed would work if I had a proxy server I could drop some custom code in for various things.

Update

I refined this thing a little further and decided to put it out on bitbucket while I work on it some more. Here's more info. You should probably assume this information is obsolete at this time.