Aside from donations how do charities make money?  What percentage of their revenues come from donations (on average) versus other revenue streams?

Adding to Jamie's answer... -Events (banquets, festivals, walkathons, shows, etc.) A not-for-profit has every revenue-generating opportunity available to it that a for-profit business has.  Some would even make the case that a good not-for-profit should be run with the same tight principles and efficiency that make for-profit businesses successful. The only financial difference in a for-profit vs. a not-for-profit is what happens to the profit.  For-profits get taxed.  Not-for-profits don't, because the idea is that they will take that money and turn it around for charitable purposes that help others, rather than profit owners/shareholders. It can actually be more helpful to think of them in terms of taxed vs. not-taxed organizations.

Another way to think of nonprofits is that the profits cannot be paid to board members or shareholders (there are not shareholders). Instead all money made must be put back into the work of the organization. As other people have said, it depends on the nonprofit as to how they earn money outside of donations. But one example is the NFL - which believe it or not is a registered nonprofit. In theory an organization is freed from paying taxes because they provide a service that the government would have to provide otherwise. But the NFL example makes it clear that this is not always the case. I doubt the government would feel a need to create major league sporting activities.