Have you noticed that coffee houses are sweeping the nation? Lattes, mochas, and cappuccinos are the order of the day and these venues are the place to be on Friday and Saturday nights. Here's a fundraiser that can work really well for schools and church groups, and which is appropriate for all ages.
If you're dealing with a smaller group, see if someone has an espresso machine that you can borrow for the evening (they'll probably be very happy to act as your barista or coffee maker if you ask them). Offer plenty of variety: ground espresso (both regular and decaf), skim and whole milk, flavored syrups (such as vanilla, hazelnut and caramel), sugar and artificial sweetener, regular drip coffee and several different teas to complete the picture.
On the other hand you might be dealing with a much larger group. If this is the case, find someone who will rent you all of the equipment and supplies (they may give you a discount in return for some free advertising). You might get a barista thrown into the deal as well. Your fundraising then comes from drinks sales. Ensure non-coffee drinks are available on the menu too, such as hot chocolate, steamers (steamed milk and flavored syrup) and juice for the children.
If you think your guests might need entertaining, have some board games on hand as a distraction. Another good idea is a poetry slam: set up a microphone and invite people to share some of their favorites poems (these can be verses they've written themselves if they like). Get the planning and preparation right and you'll find that everyone enjoys themselves.