If only we could borrow this for an afternoon!
Think of the possibilities...
http://thatvideosite.voxcdn.com/core/3406/mit_digital_drawing_board.wmv
That looks alot like Microsoft's Phyiscs Illustrator for Windows XP Table PC Edition.
http://www.microsoft.com/windowsxp/downloads/powertoys/tabletpc.mspx
I haven't played with it in a while, but I don't think you can do much with magnets on it - but I'm not
positive