My sister and I had a habit of harassing all of our baby sitters. My parents are divorced and we lived with mom, so this was a very bad situation seeing that there was often need for a sitter. We used to go to opposite ends off the house and would both start simultaneously making a TON of noise, just to watch the poor frantic babysitter run back and forth between the two of us. On another occasion, one brought her boyfriend along (!) so my sister and I chased him around the house and hair-sprayed his VERY hairy legs (pretty creative for an 8 year old). My personal favorite was when we discovered if you shook soda cans, they exploded when you opened them. Thus, our favorite way to test a new sitter was wildly shaking the can for about 10 minutes before they arrived and then the mintue mom was out the door - 'Umm, {name here} could you open this?' Then stand back with innocent eyes. We actually sent one home crying.
I hope my kids aren't like me