Create and sell a coupon book with deals from local businesses.
Cookie Sale: Bake your own cookies as a class from frozen dough.
Pizza Sale: Once again, get the class to make them.
Bedding Plants Sale
Servant Auction: Bid off students to be servants for students and teachers to use during non-class time.
Kidnap a Teacher: The class who raises the most money gets to have their teacher kidnapped for the day. The class then gets to have a fun day with movies, games, treats, etc..
School Fair: Organize a number of games and booths that the school can participate in, for a nominal fee of course, for small prizes over lunch hour or for the afternoon. Eg: face painting, basketball shoot, batting baseballs, ring toss, relays etc.. As well you can sell ice cream and other treats.
Sell Greeting Cards
Sew a class quilt and raffle/auction it off.
Make a class gingerbread house and raffle/auction it off.
Make and sell school calendars. There are some photocopying places who can do this sort of thing. Have children draw pictures for the months and pick the best 12. You can also sell dates in the calendars. People might buy them for the birthdays of their kids, anniversaries, or special events.
Holiday babysitting: Older classes can provide childcare around Christmas time so parents can go Christmas shopping. Have parents sign a release form and notify you of any medical/health concerns. Provide snacks and entertainment.
Read-A-Thon: Get sponsors or people in the community to pay for each book or chapter read for a specific time period.