We did this for an activity night at our youth group but it could easily work as a fundraiser as well.
I’m from Australia and in December it’s summer, so it’s pretty hot. As a result a lot of people don’t necessarily have ‘traditional’ Christmas meals (they have prawns on the BQQ and green salads, stuff like that). As a result people sometimes have Christmas in July meals so they can have a traditional roast dinner.
We cooked up a bunch of roasts and roast vegetable, two types of soup and a few different types of desserts. We had the youth leaders be waiters for the kids. We also had door prizes and a gift swapping game. It was a formal dinner and all the youth dressed up. We even made up menus and stuff for the dinner.
To make this a fundraiser all you have to do is advertise it at your church and sell tickets to the congregation. Have members of your youth group (and leaders) be waiters for the night. We found it useful to find volunteers who would cook a roast at home and then bring it on the night.
It was a lot of work, and there was a heap of cleaning up to do, but it was fun.
If you’re north of the equator you could do the opposite of what we did and have an ‘Aussie’ Christmas in July.