Ice skating! (If you consider it tznius).
Start a babysitting club and market yourselves out to be available to babysit (and then you’ll make tons of money!).
Start a choir and practice to sing in an old age home (to the women only of course). Or a dance?
Make yourselves a scavenger hunt (use your imagination on this one).
Go to a huge supermarket and give each other topics (ex. something very random like “computer”). Each girl has to find 3 items that have to do with that topic for under $5. Go home and figure out what you can cook with all the items.
Have a get together to watch a really amazing Rabbi Wallerstein shiur on TorahAnytime.
Make a weekly motzei Shabbos pizza making activity.
Host a Home Kiruv Training seminar from Project Inspire.
Pretend you’re little kids and play little kids games like hide and seek.