My favourite (figurable) is Clippy.
"I see you have been using your mouse"
Another cool trick:
Many people have hotkey combos on their computers for their computer graphics.
Press CTRL+ALT+ARROWKEY
Replace "arrowkey" with the down arrow to flip upside down, use the up arrow to put it back to rightside up, press left or right to turn it to the side.
(Just remember: Fix it with CTRL+ALT+UpArrow...)
This only works on some computers