Half a dozen years ago, runner-friend Pete Darmody explained the word "foamer" — a somewhat-derogatory term for a train enthusiast, aka railfan. Another such term just came up in a Washington Post article yesterday, "In Britain, bird-watching gone wild": "twitcher". A twitcher is a hyperactive birdwatcher, obsessed to the point of traveling long distances at the drop of a hat to witness a rare species and check it off on a list of observations. Wikipedia offers a "Twitchers' vocabulary" list of associated terms, including megaticks, chooks, crippler, jizz, and other odd usages.
New words are such fun!
(for a few other semi-random and new-to-me fascinating appellations see: agnize, déhanchement, diaresis, disarticulated, kenosis, kvell, plangent, postalveolar, shul, snuggery, treva, ...) - ^z - 2013-12-15