I think you got some great ideas. Most of the mama's who answered are in the age group you mentioned. However, I am probably old enough to be your mother.....I still enjoy an active nightlife. i just turned 48 and I pass for early-mid 30's and I really believe attitude has a lot to do it.
I love the True Romance/Slumber Type parties. They can be a lot of fun and no stress way to liven up your own home life!!
A fun thing could be to hop from place to place with your personal limo. Check out good clubs, wine bars, etc.
One thing I feel is very important is keeping the bond with hubby. My hubby and I stil do weekly date nights...it is a PRIORITY and it keeps us out of a rut. We'll be celebrating 21 yrs of marriage this year, 25 total together.
Whatever you do, it sounds fun and you are a good friend to do this. Enjoy!!