Take a drink: Every time you or your buddy says something like, "man I wish high school was still as cool as it was back in the days of Dazed and Confused." Take another drink: Every time Matthew McConaughey or Ben Affleck says, "man I wish my career was as cool as it was back in the days of Dazed and Confused." Note: In the unlikely event that either McConaughey or B-Affs is not present, just assume that whichever one is missing would say this every single time their character appears on screen.
Finish your beer: Every time the kid playing Mitch Kramer touches the bridge of his nose.
Have your stomach pumped: After finishing 237 beers.