http://www.quizrocket.com/patronus-test
My daughter loves these things. She can never pass one up. Today it was my turn to try it. So naturally, this was my result:

My Patronus is a Rabbit
Your patronus takes the form of a Rabbit. A rabbit is known for being somewhat shy. Similarly, you tend to be quiet around others, especially new people. However, you are very bright and alert. You are good at reading people and know who to trust. You are also nurturing and kind. You may have trouble conjuring your patronus because your mind tends to race in the heat of a battle.
As one of our members, rabbitsmba says, “Go Forth and Waste Time.” 
EDIT: Oh, and at the end they ask your birthdate, which is not so much while it’s still anonymous, but the next page wants your name and address. I found that if I tried to close this window, a popup would appear that asked if I was sure and if I hit cancel it brought up my results anyway. (Obviously my popup blocker is not turned on.) A few times I had to go back into my history and pull the results page up from there to get it to work. I don’t put my personal info out there easily, nor do I recommend it to anyone else.