I would have said cursive, but apparently looking at my handwriting I utilize it with regular writing for fluidity (such as vowels and connecting letters in a word).
So I guess the most useless skill would have to be Spanish, mainly because I never used it when I lived in Florida and I learned...
I collect historical antiques/items/replicas from my travels.
From Germany there was an antique store that (secretly) sold old nazi war medals and I managed to snag one.
From Ukraine I bought a Soviet war medal and a communist party pin.
From the Czech Republic I bought a Viking helmet replica...
I don't have a specific count for it, but World of Warcraft took about 8 years of my life from 2005-2013 (Classic all the way to Mists of Pandaria, quit after playing WoD a bit), and I guess it would be around 10k hours total for WoW.