I had this idea for a slumber party for my younger sister... I don't know if it's too little-kiddish, but I always have fun coming up with theme parties...

I thought it'd be fun to have a "Pink Ladies night with the girls." At the party you'd, of course watch Grease, have a beauty-school drop out makeover contest (try to give eachother the worst makeovers ever), and play some fun fifties music.  I also thought it'd be fun to decorate the table with old records as the chargers for the plates, and then after you eat you can decorate them into picture frames... of course you'll have to take some fun group pictures to put on them. 

And for food, hot dogs would already go along with the theme, and I was thinking any other diner food, like where they ate in the movie... like hamburgers and stuff.  I also thought it'd be fun to have a make your own milkshake bar instead of cake.... have different kinds of ice cream, and different mix-ins (shakes are the best when you just put a few scoops in a glass, add milk about halfway and mix with a spoon).

Hopefully that's not too much... I just get these ideas sometimes and I can't help but to plan all of the details, haha...

If you don't really want a theme-y party... I think the most fun I had a slumber party around your age was to make a movie w/ someone's video camera.  It entertained us for hours when we made it, and then we had a lot of fun laughing over it afterwards.

Wow, that's awesome!  When she moves up to a tricycle you should pimp that for her too!