Bags to school is a good one, we raise well over £300. Combine it with a jumble sale/car boot and go around everyone asking for any clothes they don't want to take home, which you can put into the bags.
Ladies Night - a comedian (slightly 'saucy'!), with a buffet supper, the comic also does DJing after, ours has gone down in history and tickets sell out within days!
Printer/phone recyling. Companies like Reclaim it, will provide you with a box in the entrance, for cartridges, large and small - the school will also be using up these and if you can get a local company to have a box for you too. All it needs is someone to check the cartridges are all claimable and ring the company who come and take them away and send you a cheque.
Great Weather Lottery, or local Football Club lottery, this is continual income with no input, once someone has subscribed.
Sponsored Walk, raises a lot, with a prize for the person who raises the most, have hotdogs/coffee at the start/end to make more money on!
I search other school websites for ideas all the time.