Just because you are in the trenches doesn't mean you can't have fun. Potlucks have been around forever and can bring your friends together in your home, at the beach, or on a camping trip. They can be full meal or deserts only. One fun event I attended was a pasta making party and of course the 70's were famous for fondue.
If your friends live close by try a progressive dinner. The first house serves appetizers, the second salad, the third main dish, and last is desert. The expense is then shared by the participants. This is fun at Christmas time because you can enjoy the decorations as you move along.
And, there's movie night. Rent your favorite movie, make some popcorn, and relax. Or, if you just want to visit you can put on the coffee pot and have a movie to entertain the kids.
With summer coming I just have to mention barbecues. There just can't be enough of those.