Mines a...

Paddy and Murphy are walking home from the pub one evening, when they come across a box.
They both decide to open the box and to their horror they find 3 hand granades in it.

Paddy says "bloody hell Murphy, what'll we do with them?"

"We'll take 'em round the police station" replies Murphy.

"But what if one of 'em goes off Murphy?"

"Feck it! we'll tell 'em we only found two."