I thought of a new prank last night. You would need to be very quiet for this one. If you know of someone that closes the blinds on their deck at night but opens them for the day, or has a front door you could sneak up on this is what you do.
A patio would be easier to do and be quiet on. For best effect they should be at home when you do this. If you know they are gone during the day it could work as well.
Build a snowman very close to the window with the face looking into the house. Just think how you would react when you open the blinds and there stands a snowman looking in at you.
I think this would be really funny if you could pull it off. The kids want to go out the front door to play and can't get out without moving the snowman.
Someone give this a try tonight and let us know how it works out.