So, I just picked up a Trek Antelope 830 at St. Vinnie's for five bucks, with no front brake or any sort of cables, rattlecan matte black with a Bad Religion head tube "badge". I want to convert it to a fixed-gear for a polo team a buddy is starting up soon. I've never ridden fixed or played polo: is this a nutty idea? Does anyone here play polo, and if so, would you do it on a fixie?

I have a polo bike. As much as I love fixed gear riding a coaster brake works much better for bike games. You don't have to worry about pedal strike when making tight turns and its just plain easier to coordinate chasing down a ball, using a mallet etc. if you are able to coast.

Also I don't know what a Trek Antelope looks like but your you probably want to put the biggest tires you can on the bike, flat bars work best and no cages...just platform pedals.

I love fixed for polo. Once you get used to it, you can set track stand picks. I suspect you put your foot down less in tight situations as well.