Is there any aspect of geekdom that doesn't make you look like a terrorist? Let's see:

trainspotting - bad.
planespotting - worse.
roadgeeking - they'll crack down on it as soon as they find out about it.
vadding* - bad.
almanacs - bad.

Come to think of it, is there a generic term all kinds of "spotting" (planes, trains, trucks, highway signs, etc..), watching, exploring, and all similar related activities?