One of my favorite fundraisers is to find a GOOD Chinese restuarant and do a deal with them for a mid week booking. Use either a Tuesday or Wednesday evening and get a decent fixed menu at a cost of around £7-£9 per head. Sell the places at around £12-£14 per head, profiting by £5.00 per head.
If you get enough diners you may be able to get the restuarant to put on a disco/kareoke. Ask for a disco kareoke combined so that if there's no take up for the kareoke you have a disco as a fall back.
If you do not have a chinese in the area that will put on this sort of charity evening, you can sell it to them by pointing out that they will do well out of the bar takings if the clientel are kept entertained with the disco, Tuesday and Wednesday evenings are flat nights for them, they rarely have many bookings for those evenings and obviously, you will try to get them some coverage in the local papers for putting the evening on.
Raffles do quite well on these evenings but don't wait untill after everyone has eaten before selling the tickets, do it while they are eating. If left till afterwards a good number will eat and leave, but do it during the meal and they will stay for the draw.
If you don't want to do a raffle, just print off some flyers telling people what the evening is in aid of and do a whip-round. With a few drinks in them people tend to be over generous with the whip to show off to thier friends. If you have a charity number encourage the use of gift aid envelopes, they will improve the take by 28%. This can also be done with the profit on the ticket price, but it means you have to reveal to the clientel what your profit is. Some people get disgruntled at this revelation.
I've been running this sort of event in my area for the last twelve or so years, with an attendance of around 80 people you can gross in excess of £1k.