offer to vaccum for your mom. It's a relativly easy chore, just pushing a machine around, and it gets you out of doing any studying.
Read an interesting book with a smart looking cover and claim it's for your english class
Go to you room, shut the door, and clean. Generally saying "I'm cleaning my room" sends other more annoying people away (and you don't actually have to make it look any different, just say that you tried)
Only go on facebook in 5 minute increments. If you're not seen staring at the computer for long periods of time, it is less likely you'll get told to go study.
Play with a younger sibling (assuming you have one). It's family bonding time - time that's not spent in front of a text book.
Run a load of your own laundry. If you don't already know how, hey, you need to learn someday, and if you already do it yourself, it's another chore you're doing that mom doesn't have to remind you about! Sitting next to the dryer is a warm place to read!
carry old test papers around with you. When asked if your studying, wave them vaugly and walk away.
While sitting at the computer, have a scholarship search window open so you can claim to be looking for college money.
Show your parents a review sheet that you already made. If you look prepared, you don't have to study any more.
Read this list and come up with your own creative ideas.
OK, so enjoy that tidbit, it's not often I say things like this. I am quickly losing my motivation to study for physics and therefore am entertaining myself accordingly by making up tips.
Which is better - motivational blog posts or funny ones or journal style ones? Vote, and whichever type has the most votes is the type I'll write tomorrow. If no one has voted...well, I don't know what I'll do then. But I except other seniors will vote for me. d^_^b