First of all, my parents are nosy and paranoidddddddddddddddd.
If I said, "Go away," my parents would take away my computer.. So, when they visit, I have planned my escape routes for:
If it's mom, I click to a boring site with a wall of text (lol, Smogon analysis?) or something like Facebook, Google, etc. I always have some boring site on my tabs, or else I open up Word. As long as there are no images of cartoon characters and I appear to be studying, I am victorious.
If it's dad, I minimize or log out of MSN. He doesn't care if I am into Pokemon/Anime.