I built this mini-basin a few years ago when I taught a sed strat course:
It's based on the Desktop Delta designed and published by Thomas Hickson (University of St. Thomas) - additional info available at the SERC website.
Now that the semester is in full swing, I'll start working up some new demos. The philosophy behind these demos is that 1) they show an interesting/abstract geoscience concept and 2) don't cost too much. Typically, these demos can be made for under $20 (although sometimes I'll trick them out with some additional flapdoodles (like I did with the Earthquake Machine).