I happen to know that Ronald McDonald House is a very specific, very helpful charity.
It houses parents of severely injured or ill hospitalized children so they can visit them regularly. These are serious cases that have been transferred from outlying areas to city specialty hospitals.
I contribute to my alma mater and to a local poultry group and to Wikipedia and to the St. Joseph Indian School, Lakotas. I expect this last is probably corrupt: they sent little stuff all the time and try very, very hard to get you to contribute regularly. Nothing ever actually SOLVES the problem; I think that's sort of strange. Why don't Lakotas, you know, become normal? Is there just something fundamentally wrong with them forever, as though they are all retarded for life? I am uncomfortable with this charity, but they nag me into it.
I contributed to UFO for a couple times, but I don't like all the militarism.