You're probably not going to want to post this on your blog, but here are 10 things you can do while visiting friends' houses:
1. Reprogram their robotic vaccuum cleaner to go on in the middle of the night.
2. Stick a toothpick in their front door keyhole and break it off.
3. Replace the sugar in their little bowls with salt.
4. Place a bottle of Budweiser hidden on the top shelf of their freezer.
5. Tuck a sausage behind the cushion of their sofa.
6. Put their house up for sale on Craigslist really cheap, then ask the buyers to call late at night because you work until 11 p.m.
7. Print a "Quarantined" banner and tape it to the bottom of their garage door. (They'll never see it because the door is shut when they are home and only open briefly when they leave).
8. Turn their backwash plumbing switch on for the swimming pool and see how much water will drain out during the normal filtration cycle.
9. Put an open can of tuna on their engine block and close the hood.
10. Change the message on their answering machine to: "You have reached the Contra Costa Sperm Bank. To make a deposit, please press one, again, again, again, again, yes, again, again, oh baby, again, again, almost there, again."