Yeah it happens every so often, sometimes the goalie is caught not paying attention, sometimes the puck takes a weird bounce or tip, either way it's always hilarious.

My favourite ever was Vesa Toskala letting in one from 200ft back. I was watching the game with a bunch of leafs fans at the time and their reaction was priceless.

https://www.youtube.com/watch?v=eipJqVmz3X8