I'm sure the UK guys saw this story in the Mail, but for those that didn't:
Father-of-two poses for photograph after digging up unexploded anti-tank grenade | Mail Online
The homeowner found the UXB in his backyard, and thinking it a piece of a lawnmower, brought it in and photographed himself with it. It was live.
Luckily, he had second thoughts and did a bit of interwebs research on h is find...and then called bomb disposal authorities.