Humane Society of the United States (HSUS)
You likely have seen the commercials on TV of the HSUS. They show pitiful pictures of abused animals and ask for donations.
In spite of these heart-rending images, the HSUS actually gives less than one percent of the money from the donations to animal shelters like the local SPCAs and Humane Societies. They spend most of the money in lobbying efforts to ban hunting, and to put bans on keeping pets, eating meat, or wearing fur.
A very useful site: HumaneWatch reveals the gory details about the HSUS.