Watching the germination of a broad bean seed makes a fascinating windowsill project.
Broad beans are facinating to watch.
Take a cardboard tube with some kitchen paper rolled around it (we used red tissue paper) and place it into a clear plastic cup with some water in the bottom. Wedge a broad bean seed between the cup and the paper. Keep water in the bottom of the cup and it will travel up through the cardboard providing the bean with enough to get going.
When the plant gets too big, pot it up in some compost.