Hasher, as in a member of the H3 (Hash House Harriers). All H3 members are called, generically, hashers. H3 is the biggest running club in the world.Now you have one more bit of data to relieve yourself of one more iota of ignorance. Don't you feel smarter already?
http://en.wikipedia.org/wiki/Hash_House_Harriers "The Hash House Harriers (abbreviated to HHH, H3, or referred to simply as Hashing) is an international group of non-competitive running, social and drinking clubs. An event organized by a club is known as a Hash or Hash Run, with participants calling themselves Hashers."