Guatemalans throw harvested corncobs onto their roof to dry out for months until it can be ground into cornmeal; this was done at house we rented. It was a cinder block house with a flat cement roof with a 1 foot tall retaining wall around edges (keeps corn on roof). So there was a foot of corn covering entire roof (like a Guatemalan version of Chuck-E-Cheese ball pit).

My companion and I were on roof horsing around and I extended my arms straight out to my sides and did a plank fall backwards. It was all fun and games until I laid in corn pile and looked to the right and saw a piece of re-bar sticking straight up an inch from my temple. The idea of re-bar going through my skull still haunts me.  

The stupid things that 19-year-olds do.