christmas cracker joke

last night was my astronomy department's christmas party (yeah, i know its still november). the tradition in the UK at a christmas dinner is to open a christmas cracker, which looks like a cardboard toilet paper roll wrapped in shiny paper! the cracker makes a loud 'crack' when you open it, and inside you find a paper hat to wear during the meal, a tiny toy you can play with until it inevitably breaks, and a joke or riddle or motto!

i received a joke in my cracker and surprisingly, it was pretty good!


Q: why did the scientist install a knocker on his door?






A: he wanted to win the No-bell prize!