Hi!
I have a 20 month old. We go to the YMCA everyday during the week for 2 hours in the morning. She plays with her friends and I workout. It is a lifesaver.
We also frequent the library, nearby parks, Explorium (local childrens museum, we purchased a membership), the mall (they have an indoor playground, and any local kid friendly event.
We try to have at least every other afternoon out of the house. Our mornings are basically breakfast, gym, home for lunch and nap. On the days we are home I choose activities that allow me to get something done as well. We do a lot of art type stuff, playdoh, markers, paint, crayons, water colors...she loves that stuff.
A month ago I went to the pbs websight and read a bunch of stuff about developmental activities and we have been doing one "theme" a week. It takes a bit of planning but she loves her little 5 minute "lesson."
Hope that helps.
Myia