I introduced the game to my oldest brother and some of his friends last Saturday, and we made a rule so that if you called a player by his name instead of his hero, you had to take a drink. We didn't really experiment with other rules, but you could also have rules such as taking a drink whenever one of your hero takes damage or whenever your equipment or ongoings are destroyed take a drink for each one destroyed.
Yes! My housemates and I we discussing this. We're students (read:alcoholics) and were going to play it. "Shot whenever you take damage" and "waterfall throughout the Argent's turn" were proposed and lead to giggles over how very messy, how very quickly it would get.
Alas, we were too scared of spillages ruining our cards.
Cameo: Whenever a character whose card is in play appears on the artwork of a card played from another deck, everyone takes a drink. (Mostly stuff like Heros and Villains, but sometimes you'll get cases like Macbre Spectre on Throat Jab or whatnot)
Waste Not: Whenever you don't use a power, OR don't play a card, but not when you skip both for the extra card, take a drink.