Old-fashioned tea party complete with dolls and stuffed animals, including lots of chairs and tables for human and inanimate guests if you can pull it off. Pretty tablecloths, tea sets, tea cakes, real tea or cold juice in fun colors, etc.
Paper dolls, either ones from pre-made books or ones to color.
Have the guests write and perform a short play, in costume with dress-up clothes. Or, do the same but make it an unwritten improv play. Give them hints to keep the action going, or style/scene changes like in Whose Line Is It Anyways.
...my brain is dying from lack of sleep or there'd probably be more. Good luck and have fun!
Any and all ideas welcome. Recipes, crafts, activities etc. ANYTHING!