Ultimate is a team sport. It is most easily described as a non-contact cross between American Football and Netball which is played with a frisbee, or, as we call it, a flying disc.

You can play it indoor, on a basketball court, or outdoor, on a larger field. Outdoor is real Ultimate, so we only play indoors on winter evenings when it is too dark to play outside.

Each team has seven people on the field at any time (four for indoor), and the idea is to score goals by having a player on your team catch the disc while he/she is inside the other teams endzone (indoor this is the keyhole on the basketball court). You can not run with the disc, and you have 10 seconds (the person marking the person with the disc counts to 10) to make a pass once you have caught the disc. If the disc hits the ground, is intercepted, or it goes out, then the other team gets to pick it up and go on offense.
Outdoor the field is 64 metres long and 36 metres wide, with a 18 metre long endzone at either end.

You get one point for each score, and after every point teams change ends.
A full length game is the first team to 17 points with a 100 minute time cap. However this is often reduced to 15 or 13 with a shorter time cap during tournaments where 3 or 4 games may be played in one day and time is tight.

The unique thing about Ultimate is that there is no referee. Every player knows the rules, and is expected to play within them. This idea is called the 'spirit of the game', or just 'spirit' for short. If there is any contact between players (and one calls a foul), or any other kind of dispute, the players sort it out amongst themselves.

So there you go. That's the basic idea of Ultimate.

For more info check out PlayUlty.com