Some basic terms you might want to know if you are playing cornhole.

Cow Pie
Landing a single bag on the board scoring one point.
Blocker
Landing a cow pie on the board in front of the hole effectively blocking the hole.
Cornhole
Landing a bag in the hole scoring 3 points.
Back Door
Scoring a cornhole through a blocker.
Dirty Bag
Any bag that first touches the ground and rolls up onto the board.
Honors
The team that throws first.
Hanger
A bag that is hanging and could potentially fall into the hole.
Sally
A bag that doesn't make it to the board.
Skunk
A game ending 11-0
Slider
A bag that lands on the board and slides up into the hole.
Swish
Just like basketball the bag falls through the hole with out landing on the board first.

Once you have the terms down you can head over to the rules page and get all the rules on how to play.