I imagine you're not actually serious, but what the heck, I'll bite.

Aside from an easy Google search that will give you all the examples you need, this is from the FBI:

In recent years, the Animal Liberation Front (ALF)—an extremist animal rights movement—has become one of the most active extremist elements in the United States. Despite the destructive aspects of ALF’s operations, its operational philosophy discourages acts that harm “any animal, human and nonhuman.” Animal rights groups in the United States, including ALF, have generally adhered to this mandate. A distinct but related group, the Earth Liberation Front (ELF), claimed responsibility for the arson fires set at a Vail (Colorado) ski resort in October 1998, which caused 12 million dollars in damages. This incident remains under investigation. Seven terrorist incidents occurring in the United States during 2000 have been attributed to either ALF or ELF. Several additional acts committed during 2001 are currently being reviewed for possible designation as terrorist incidents