A weird hobby or collection
I don't really have a weird hobby. I used to collect things when I was a kid, but not too much anymore. The only thing I really try to collect is magnets from everywhere we have been. Our fridge is littered with so many different magnets (and we really try to vary the type of magnet we get) to represent our travels. My favorites are a Texas shaped magnet with a scorpion in it (from San Antonio - we got engaged at the Alamo), a pretty lighthouse from Mystic, CT, and of course.....one we bought in Serbia that is Vlado's name in Cyrillic.
I'm not sure if that counts as weird. Honey does have a collection of antique mortar/pestles (he's a pharmacist so that's not really weird either).