Go to some nearby chain restaurants (I say chain because most of these have set procedures for these things, though if you have a good relationship with a certain local restauarant/bar you could approach them too) and ask about fundraising. I'm doing a fundraiser with a nearby establishment, where they send me 500 flyers and I can make as many copies as I want. The fundraiser is for however many days I choose, and I chose three consecutive days in mid-June, during which any person who eats at the place and has a flyer on hand, 15% of the total bill goes towards my charity.