We have a mom at the gym who organizes our fundraisers. They do frozen pizzas, cheesecakes, cookie dough, holiday wreaths, wrapping paper, Yankee Candle. Maybe even a few more that I don't remember. I personally am not a fan of the "mom and dad sell this stuff" fundraisers. I don't work outside the home, and DH does not work in an office, and I don't want to sell overpriced stuff to my family. While they are not my thing, a lot of people at the gym do them. They are spread throughout the year.
Our biggest fundraiser is a Beef & Beer. Growing up in central PA, I'd never heard of this, but they are huge in Philly and the burbs. Basically you rent a hall, get a couple of kegs, have roast beef sandwiches and sides catered, and get a DJ. Sell tickets for $25 per person. Then, you also solicit local businesses for prizes. Maybe a salon will donate a cut and color, mani pedi, etc. sometimes a travel agent will do a weekend getaway, people donate tickets to a sporting event, etc. Try to get a range of things. Also have each team put together a prize basket with a theme. Then at the event, you sell chances for the prizes. So many tickets for $10, and then people put their tickets in a bag next to the prize they want to win. There is usually a 50/50 too. It's a fun way to get to know some of the other parents, and the tickets are an easy sell--lots of people don't mind spending $50/couple for an adult night out with friends.