As Peter Bagge notes in his November feature, many third-party candidates champion instant runoff voting for its potential to loosen the duopoly's stranglehold. Like Bagge, I have no idea whether IRV will work as advertised, but I'm happy to give it a shot, and happier that San Francisco is instituting it for local voting on Tuesday. Thanks to Starchild, perennial Libertarian candidate for something and the LP stalwart who holds it all together in the city of St. Francis, you can get a look at how instant runoff voting works in this mock vote for the SF School Board. Of course, while you're there (sneeze, sneeze), you can show your support for Starchild, the one candidate (running on his record as a public school graduate!) who can really work out the kinks in the school system.
Update: In the comments, Ironchef points out that the School Board mock voting page is an example of Approval Voting, not Instant Runoff. Here's an explanation of IRV, with an endorsement from 1980 footnote John Anderson. I don't have enough of that thar booklarnin' to comment on the pros and cons, I just know a vote for Starchild is a vote for the future!