Draw triforces, lol.
Been doing that in Biology as of late. That, and speculate on Zelda timeline theories.
Oh, my favorite one. Whip out the old DS. I spent my entire math class playing it. Don't even need to hide it. I ace the class, and it's an Honors one, too. I simply see no need to pay attention to the notes we do in class, and since the whole grade is Homework/Test related, my teacher doesn't care.