My dad is one of 7 kids. He has 3 brothers and 3 sisters, so you can imagine how many cousins I have and now nearly twice that with second cousins as we all become parents ourselves. Needless to say we wouldn't all fit in someone's house so we rent out a banquet hall each year and have a ginormous feast. Then we usually play poker and other card games because my family are a bunch of gamblers.
There's usually some other stuff that goes on too.