Dog parks have become quite the place to hang out if you have a dog. If you want the benefit of exercise for your dog (s) or if you just want your dog to enjoy playing with others a dog park provides this. Some parks are small while others have lots of space for dogs to roam -- all off leash. Above and below are photos of a large park where I take my dog every day to run and greet other dogs both large and small. She loves it.
Here are some woman that have been enjoying watching their dogs as they socialize with other dogs -- while at the same time doing a bit of socialization with each other.
If you have thought about taking your dog to a dog park check out this Wikipedia site to find out the particulars. Also check with your local municipality for locations.