Quick, is there an amusing Blackboard related pun? Hmmm I can't think of one so I'll assume there isn't. So, straight to it.
For work I made a small blackboard to use at events. I liked it and so decided to made one for my nephew's birthday, for him to draw on. Made purely from scrap or recycled wood (the doors of some old cupboards and part of a futon) and a tin of blackboard paint.
This is how it turned out:
and thus, a blackboard. Looks better with his drawing on it...