you can ...
Football, swimming (install a small plastic swimming pool), etc.
You could play hide and seek in the backyard, ride a bike, go on a walk, and many other things.
You could get a magnifying glass and check out the insects and things in your backyard. You could play sports. You could invite friends over and have a scavenger hunt.
you would have more fun at a dignified backyard barbecue
Things in the backyard include flowers, fence and flies.
fun
Because they both have active things and also they are very fun
There were some great things to do for free or inexpensive family fun. Some ideas they had were family game night and camping in one's own backyard.
One fun thing would be capture the flag! some other things are: tag, hula hoop contest, or hide something like a Frisbee in your backyard, and have some people try to find it!
Ray moved the hose.
Ray moved the hose.
I believe that good toys for a large backyard are things that can be used at any age. For example, a swing would be good as long as it is suitable for adults as well because it will be used a lot. I would also suggest some goal-posts or a basketball hoop as these can take a lot of use. Perhaps a trampoline or something similar would be fun as well because it keeps children active and can be used often.