Dad's family, when grandparents were still here, it was fairly evenly split. My grandpa sat and watched TV, but that was how he always was. Nothing was going to change that. Dad and uncle were in charge of the main courses and heartier side dishes (meats, beans) and my grandma and aunt 1 did the deviled eggs, cole slaw, all the finger foods, and set up the tables. Everyone pitched in with cleaning, usually the grandkids did the dishes afterwards. It was an efficient system.
When grandma died and uncle took over hosting, it was still pretty much the same. Dad and uncle did the main dishes, aside from aunt 2's chicken dumplings. Aunt 1 and mom and I took over with the deviled eggs and slaw and finger foods, but uncle and aunt 2 did all the cleaning. Nobody else was allowed to, we were guests.
At mom's family gatherings, it's all potluck buffet with paper plates, so there's no real division of labor there.
In my friends group, I've noticed that for actual in-house meals, the women do the cooking and the cleaning up, the men tend to man the barbecue. Since we split fairly evenly barbecues and actual meals, it works out.
I will say one thing, though. Whenever I'm in a kitchen cooking, I'm also cleaning. When I made dinner the other night, my boyfriend was shocked when he came home and it was ready, and half of his pots and pans were clean, too. He's the type of person to set something down and let it heat up, I actually cook from fresh and figure if I'm going to be in there, why not make everything easier on myself. I've found that I don't know many males who have that mindset, it seems to be a predominantly female mindset to clean as you go. Has anyone else noticed this?