Hi A.,
Have you thought about joining a play group? We have a play group that meets once a week if you are interested. Playgroups have been a life saver for me in keeping my VERY active 3 year old daughter busy. Also, we try and do at least one craft project a week, and she loves activities like flash cards, and cooking with me. Also, if you set up simple short activities that they can get to easily, such as books they can look at, pretend toys (food, clothes, dishes, etc.) that is helpful too. Finally, I try and take my daughter for a "treasure walk" every day. She takes her basket and we go for a short walk where she can look for and pick up "treasures" (rocks, sticks, etc.). If you are interested int he play group, let me know and I can send you more info. It is free.