Depends on how extravagant it is.
One experience I had was the company put in a bar tab, it was run dry by about 9pm, then we moved onto shots and buying our own drinks. It was a hard night, but damned harder morning.
Another do I had was (same company) hired out vector arena, a who-dunnit- type thing. Free drinks and a meal, they even hired out one of those photo booths. No one really paid attention to the who-dunnit. Needless to say, nearly everyone left a bit tiddly
Also worked at places who do a smaller do's, like a BBQ on the beach, or one company we went on the luge which was quite neat.