Several years ago we were at a children's museum where they had different stations set up for children to "discover," "experiment kinesthetically," and "manipulate objects." Those were the days when I would join every museum within 50 miles of my house so that my kids could have as many "tactile experiences" as possible somewhere besides our house! (Oh, our poor carpet in those days!)
One day there was a station set up with gobs of these 9 oz. clear plastic cups for the kids to build with.
I could not tear my son away from them! I bought a 200 count bag of them the next time I was at Sam's, and they still get played with!
They have mostly been used to build towers and walls, which are then promply knocked down- the fun part! (They have survived many a radio-controlled car!) We have also used them for science projects, for planting seeds(and watching the roots), and for mixing paint.
Tons of fun, for less than $8. Works for me!
For more fun tips, visit Rocks In My Dryer. Hope your Wednesday stacks up to be a great day!