My father always warned me against playing catch at night time ... and with live ammo.   He absolutely forbade me from playing catch with hand grenades, especially after it got dark outside.   But not everyone had as capable a parenting as I did.

Reuters reports three youths died in Novi Grad, Bosnia after a hand grenade went off during a game of catch at 2 o'clock in the morning.   News reports said "It was not clear why the grenade exploded."

I wasn't there (I do have that cool picture of the game) but I would like to suggest that the reason the grenade exploded was because the pin fell out.   It was probably too dark out for anyone to notice.   If you're going to play catch with grenades, you really should do this only during daylight hours in order to avoid these kinds of accidents.