Need birthday party ideas for (soon to be)15-year-old DD

[Mom-to-3]

DD is turning 15 this month and would like to have an all girl party. She is a freshman and is torn about whom to invite. She has
*new friends at the high school,
*church youth group friends, and
*girls from her magnet school last year.

Does it work to mix groups of girls who don't know each other?

Anybody have any ideas for activities? Bowling is fun, but another girl did that 3 weeks ago.

Help..........

 

[The Mystery Machine]

I would suggest 3 small get togethers. Better for dd to be more intimate with her friends.

Dinner/Lunch & movie
Amusement Park
Sleepover with one of the groups (definetly wouldn't mix groups at your house, at the very least)