I learned that "Americone Dream" is the best ice cream flavor ever invented. :)

Seriously:
I learned how rice cookers work. That is, I learned the actual mechanism that keeps them from turning rice into lumps of carbon.
I learned correct soldering technique. I'm still no good at it but now I understand why I've always been worse at it.
I learned a few new ways to cook steak.

Certainly others. Those are the ones that come to mind.