Beer pong consists of ten cups (and two water cups), two balls, a table, and two teams of two people. The concept is pretty obvious of course, but the rules are based off whatever the host of the party wants them to be. No exceptions. Here is a list of possible rules.
Rodeo- When one team shoots, misses, and gets the ball back, at the end of their turn they get a chance to make a cup by throwing it behind their back. This is worth two cups if made
Death Cup- If one team makes a cup and the opposing team fails to remove said cup from the table, and the other team makes the same cup in question again, this is Death Cup and the opposing team looses and drinks all the cups on the table. (see recycle)
Recycle- This is when the winning team chooses to recycle their alcohol for the next game, even if death cup happens, because they do not want to share it with the opposing team.
Both Balls Same Cup- This can either be worth 3 cups and balls back to the team who made them, or 2 cups and balls back, host's choice
Rerack- There can either be one or two reracks, host's choice.
Air Ball- The team that Air Balls drinks one cup of opposing team's choosing, unless it is the final cup
Automatic I- If there are only two cups remaining, the team can use the Automatic I rule to straighten them up.
No Shooting While Drinking- If a shot is made while the opposite team is clearly drinking and has no way of knowing the game is on, the shot is canceled.
Cory: You playing beer pong at Orey's tonight?
Greg: Yeah man, but i need to know his house rules so i can keep up with what is cool and whats not.
Cory: Yeah man, he will hit us up with the essentials.