food
I always wonder how people came up with the idea to eat certain ridiculous, visibly inedible things. Take beans for example. We take for granted how totally inedible these little fruits of goodness normally are. How the hell did someone get the idea to take the rock-hard little pods, soak them for a god-forsakenly long time, and then eat them? I'm guessing it was probably by accident rather than trial and error, though I can certainly see some comical situation unfolding as neolithic humans get the idea that maybe soaking ANYTHING long enough makes it edible:

OG: Yo, grok. You soak rocks?
GROK: Duh. I soak rocks long time. Soak good.
OG: We eat?
GROK: OK, we eat. You try now. (laughs evilly)

Or rice. Same thing. Howd'ya figure boiling it just the right amount of time takes it from a stomach-mangling little grain into soft, fluffy goodness.

Justin thought of one even I can't top. Coffee. Who the HELL got the idea for that?

Were they like "hey, maybe if I take these weird beans, dry them, fire roast them overnight, pulverize them into pulp and strain water through them they might taste good!" Boy, I bet they were sorely dissapointed when it tasted like SHIT. And I bet they got the last laugh, too, when they drank it anyway, told everyone it was good, and started an ancestral craze that would birth Starbucks some odd millenia later. Ha, ha. I'm laughing now.