Fullscreen API is perhaps known for its spoofing potential, leading to major browser vendors canvassing for the implementation of an overlay to notify users when full-screen is activated.
A nice flash whiteboard resource where users are given a multiplication question to answer by dragging along a numberline.
http://ictmagic.wikispaces.com/maths
A great division/multiplication flash based whiteboard resource where users arrange numbers and signs in the right order.
http://ictmagic.wikispaces.com/Maths