Heres a great Broccoli casserole recipe that goes a long way and is easy to make.

Frozen chopped broccoli (8 boxes or 4 bags)
Cream of mushroom soup (4 cans)
8oz. bar of cream cheese (4)
ritz crackers or cheeze-its (4 rows of ritz or 1 box of cheeze-its)
butter and diced onion (4 sticks butter, 2 onions)

Cook broccoli as directed and drain, stir in soup and softened cream cheese until smooth
Saute onions in melted butter in frying pan
crush crackers and add to butter and onion mix. pour broccoli mix into baking pan and top with cracker mixture. bake at 350 for about 20 min.
the great thing about this is you can make it in advance and freeze it until you need it. if you do this than you can defrost and bake at 350 until the sides of the casserole start to bubble. i just had a baby shower for 125 people and there wasnt a drop left it was delicious. You may want to just cook a couple of hams and Roast beefs and slice them up on platters that always works well with a big pan of roasted potatos. have fun at the party.