Same of them do sound rather far-fetched, don't they? Which ones did you find to be incorrect, out of interest?
E.g. that a duck doesn't produce an echo (check mythbusters ;-)). The spider silk one if badly phrased. Orthodox jewish women also go "commando" (but I don't know if they use bikini wax). There is nothing like a "lead based pencil", it's graphite. There is no explanation for yawning.
There is no "first house" in Skyrim, it's open ended. And the one in Whiterun actually costs 6.000, but you only have to pay 5.000 (due to a bug?) when you have less than 6.000.
And, of course, the urban ledgend of the atari E.T. cartrige landfill.
I guess there are more, but those are the ones that jumped at me. And many others are, well, not that impressive.
Still enjoyed it greatly, though!