LOL Oh I babysat my three/four year old niece this last summer. I know what you mean. Let her make collage pictures cut from a magazine and glued with a glue stick. Sing songs and play hop scotch. Lots of healthy snacks and v8 fruit juices. No Sugar!! You will be sorry if you do. LOL! Also if you google paper dolls, there are many print outs that are nice. Coloring and those color books with the dot that turn colors with a water and paint brush are fun for them. Check you local library, they sometimes have story time there with guest speakers. The museums often have child exibits. Then there is the YWCA. They sometimes have swimming lessons or other activities for kids.
If you enjoy walking aroud the block, this is very good for the little one too. (It might wear her out)
Finally .. Dress up! If you have things that you think she would enjoy dressing up in, make up a box of it and let her play with it. Hats are a plus... LOL!