Here's an easy and inexpensive learning game I have been doing with M lately. From colored cardstock I have cut out basic shapes. I lay them out in front of M and ask her to pick up the shapes by name. Once she has the correct shape in hand I ask her to put it somewhere specific. "Can you hide the red circle in your toy chest?"
Once all of the shapes are hidden away I ask her to find them one by one. "Can you find the blue triangle?" Usually she can remember where she put them but sometimes she needs some help. It's a good way for an 19 month old to work on her memory skills as well as learning shapes and colors!