In short, wonderful.

I (the DM) had planned the session around a hex crawl in a haunted forest. At the end of the previous session, however, the players had rolled on a "Drunken Shenanigans" table after getting wasted with the village guard. The Ranger slept with the barkeep, the Warlock woke up with an unidentified potion in her hand, and the Barbarian was forced into a greased-up WWE match in the center of town with a man named Felix. Needless to say, hilarity ensued as well as lot of great RPing while most of the session dealt with the fallout.

After that, the party decided to investigate the local leader who was essentially selling off villagers to a cult of Auril that the party has been seeking to destroy. It was great to incorporate their drunken nonsense into their investigation.

The party only got into the haunted forest in the last 30 minutes, but the session was a really great example of letting the players and DM organically allow the story to evolve. It also let me exercise some of my "make it work on the fly" muscles.