Our dining / learning / making room.
I've found that one of the best ways for us to save money is to stay home. It isn't very popular in today's culture, but it works for us.
For instance, we don't sign up for many field trips and we don't take outside academic classes. We're home learners, not car learners (although that works for many families). Field trips and classes almost always cost money, even if it is just in gas to get there.
We do our best to eat at home, saving restaurants meals for special occasions or social gatherings where we have no other choice. Cooking our own meals is much less expensive than restaurant meals, and is healthier too.
Speaking of those social occasions, I do my best to suggest that we meet at our home (or someone else's) and have a potluck instead. (Unfortunately, I do get turned down most of the time unless people want to come here.) Even if I provide the entire meal I still spend less than I would to feed my family of four at a restaurant.
We try to hang out with friends at the park or at home. I have never found it enjoyable to try to visit with mamas and kids at a bookstore, toy store, coffee house, or pizza parlor, and I think habitually hanging out at places of business without making a purchase is unfair to the businesses.
We watch movies at home. Using Netflix or renting a Redbox movie is so much less expensive than going to the movies at the theater, even with discount tickets. (We do use the discount tickets to take the boys to one or two highly anticipated movies per year, and about once a year for a date night.)
We entertain ourselves at home. We can listen to records (or other music), play board games, watch a recorded TV program, or have a family music night, all for the money already spent on music, games, a TV system, and musical instruments.
Of course, being home results in savings so many other ways. If I am home I have time to cook and bake, to sew and mend, to make gifts, to grow food (I'm working on this), to clean my own home, to hang laundry, to do small repairs, and much, much more. If I worked outside the home then being home as much as possible other than work would be that much more important in order to live a frugal life.
I hope I have helped my boys to feel deeply connected to home and absolutely satisfied to be here. I don't want them thinking that everything good happens somewhere else. That is one reason we make a point of enjoying our evenings together by playing games, listening to or making music, and doing other active things together (versus only watching TV which is very passive).