Here are some I thought of.....
You can always put nails under their tires. They wont be get flat until they almost get to work or about to leave work.
You can go to the firework store and buy stink bombs. Break one in their car and it will smell like the most horrid rotten eggs for months
You can treat your self to a gas powered remote control car and drive that loud SOB around in the culdesac.
You can throw some poison Ivy in their mailbox or in/on their car and they will grab it to get it out/off before even thinking.
You can get a heavy duty chain and lock and chain their two cars together by the wheel spokes or tow hooks.
You can get some big game fishing line and tie it to the posts going across the front porch and watch one of them bust their ass down the steps getting the morning paper.
You can plant a bear trap in their garden.
You can set up a bunch of yard sale/garage sale posters up with their address.
You can pick up a flattened squirrel from the road, put it in a nice box with a bow and a note reading something like "Congratulations for winning PetSmart's free pet giveaway".
Wait for the newspaper guy to drop of the paper at 4am. Go get their paper, pull the paper out and unfold it, take a log of a dump, fold the paper back over and place it in the bag. Then tie the bag so they would not smell anything. They get the paper, shortly there after untying the bag and pulling out the paper with your log on their kitchen table.
