Mayweather vs. Pacquiao -- The Drinking Game

While Manny and Floyd are knocking each other's heads off, millions of fans will be getting knocked on their asses ... from dat drank ... thanks to a host of drinking games that are taking the net by storm.

The games are catching fire on social media ... and although they vary in the rules and conditions of the swallowing of the booze, it's clear that everyone who participates WILL BE HAMMERED.

Here are the rules to one of the more popular games making the rounds at the moment:

-- If Justin comes out with a stupid grin on his face 1 shot.

-- Every time they show a celebrity in the crowd 1 shot.

-- If they mention Floyd's dad 2 shots.

-- If they mention Manny's politcal career 2 shots.

-- If they mention Mike Tyson dissing Floyd 3 shots.

-- If the winner DOESN'T thank God first 3 shots.

-- 4 shots for a punch below the belt.

-- 5 shots for a draw.

-- 5 shots if Pacman gets knocked out.

-- Finish the bottle if Mayweather gets knocked out.