This activity is a variation on something I found on 1+1+1=1's tot tray link. If you haven't checked this site out, there are so many great ideas here.
I purchased an inexpensive Parmesan cheese shaker and some colored toothpicks at either Wally World or the Dollar Tree. The object of the activity is to have your preschooler use his fingers to poke the toothpicks through the holes in the top of the shaker. This strengthens the finger muscles, improving the fine motor skills they need to write.
Mr. Two (my preschooler) loves to use his pincher fingers to poke the toothpicks into the container's holes. Mr. One (my kindergartener) liked using the toothpicks to make pictures. Together, they also sorted the toothpicks by color and took turns poking them into the container.
If you want to go really crazy, give the kiddos some marshmallows with the toothpicks and let them create three dimensional works of art with them. Fun times.