Sure, you can get "blackboard" paint at the hardware, but some smart student entrepreneurs experimented endlessly and found a concoction that erases like a dream. It's called Idea Paint.
CNBC profiled it on their "How I Made My Million" series. See this at http://www.youtube.com/watch?v=QqU_cChhAaY.
This stuff is now available in 15 countries.
The young smarties even heard of a school system that was taking down the blackboards and buying white boards--they said, basically, wait, do you have walls in those classrooms? The rest is history.
Yes, almost everything has been done--but this does not mean creativity cannot improve on almost everything. A lot is in the marketing. Go to http://ideapaint.com. Notice they sell markers, scrubbers--that's where the millions come in--always thinking.
