This is something I whipped up a day before Clock Day; it pleasures me to know that I'll be partaking in a special NG day. Nothing serious, though; a simple platformer. Note: I did not use any tutorials; just my knowledge of hitTest and the Drawing API.
Relatively simple. Use the LEFT and RIGHT arrow keys to move, and SPACE to jump; draw lines with your mouse, press the left mouse button down and drag to draw, and release to stop drawing.
Click the 2011 button for a special surprise! (Hint: Clear)
You cannot have walls; each drawn platform, regardless of shape, is determined as a platform. So just draw a simple vertical stick; it'll act as a huge platform. Just press the SPACE key and et voila! You've travelled new heights!