You need two teams, a baseball diamond, some plastic cups, and A LOT of beer. Place a full cup of beer at each base. The runner may not proceed until the cup is empty. For example, a double would require the batter hit a fairly long ball, run to first base and down the beer waiting there before proceeding to second base and downing the beer there.
Home runs are rare.
It is normal for the batting team to make sure that all cups are kept full, as runners can't advance without drinking.