Doesn't seem like a good idea to out someone at the office. I'd say let them pick the time and place.
We have a yearly golf outing with steak fry and overnight at a hotel. Usually ends up being a pretty late night with lots of drinking and cards. Mostly males of all ages but a few females and everyone has a good time.
Have done ICubs game in past.
WIne tasting in Waukee followed by a nice dinner at Rubes
I would personally love canoeing, but that seems like the type of thing that would be very hit or miss on interest level amongst a group that size.
tube ing on the DM river with lots a booze