Great game. We play it where team one has one person throw and then a person on team two gets a rebuttal to negate their points. Then it switches ( two throws and team one negates). Also we play where if you go over 21 you go back to 13 - similar to how bags (corn hole) is played.
We have implemented another scoring opportunity called The Sixer. If the thrower is able to land the disc inside the top of the can they are awarded six points.
I'm going to take a wild guess that this game was invented by someone who couldn't manage the coordination to catch a Frisbee, and probably weren't too good at throwing long distance either, because aren't they both part and parcel, or the dual Holy Grail of "playing" Frisbee in it's purest and simplest form?