Ever Since Plants Vs Zombies was first released I have loved it. When I love a game the first thing I want to do is make a drinking game for it. unfortunately Single player games are not really conducive to drinking games so for a long time it was just not possible
However the recently released XBLA version fixed that lack, adding multi-player in both Co-op & Vs modes.
This drinking game is based on the Vs Mode, and I recommend players switch sides regularly. You should play winner stays on if in a big group.
Powerless Player – Every time one of your sunflowers or gravestones is destroyed, have a drink.
Last Ditch Defence – When playing as Plants, if one of your lawnmowers is activated, have a drink
Sharpshooter – When playing as Zombies, have a drink when you lose a target.
A Lack of Brains – When the match is over, the loser should have two drinks
A good offence is the best defence – If you manage to beat the other player without having to use a lawnmower as Plants, or losing a target as Zombies – the loser has an extra drink
Having tried this a number of times now I can confirm that this game ranges from Moderate to Heavy based on your opponent