EN Publishing's "Tournaments, Fairs and Taverns" was one of the earliest d20 supplements, and one of the most welcome, in my view. To me, these social opportunities have always been important to the lives of characters in my RPG settings, and to have innovative, thoughtful rules looking at them was a big help. Now they're back with Fourth Edition looking at some of the same material. In this well-priced supplement, they look at drinking and how it can add to your fantasy game.
Along with a system for drunkenness (it uses increasing Endurance checks and a measure called "shots", for reasons that are obvious), it also contains a list of many fantastical drinks and their strange effects. A hilarious option allows players to choose whether their characters are friendly drunks or unpleasant drunks, with effects on their skills when they get blasted.
All in all, it's a well-rounded look at light-hearted drinking, a staple of many fantasy adventures. I heartily recommend it with a loud "bottoms up!"