My daycare has a preschool program:
http://www.heritagechildcare.org/index.php?option=com_content&view=article&id=49&Itemid=18
We absolutely love it there! It's about 1 mile West of the Rhode Island Ave/Eastern Ave intersection. I don't think it's play-based though. The kids do get a lot of outdoor time, they have a wonderful playground area. The preschool teacher, Ms. Maha, has been there for a long time. The director there is amazing.
I will also say that I have heard bad things from neighbors about Gateway center in Mount Rainier. I have multiple neighbors that pulled their children out of there.