Merlin
From DrinkiWiki
Take a small drink (small or you will be legless before one third of an episode) when:
Arthur insults Merlin
Someone uses magic
Uther becomes angry
Merlin goes in the stocks
The dragon speaks
Gwen flirts with someone
Swords clash
Take two drinks when
Gaius past is spoken of
Arthur compliments Merlin (three drinks if no insult is involved)
Someone finds out about Merlins secret
Empty the glass if:
Uther shows humility or remorse