There's such a variety of games. Many are more fun if you can recruit several players.
Hide and Seek - of course! Check out my user name! ("olly-olly-oxen-free! come out! come-out-wherever-you-are!" I grew up on a suburban street filled with dozens of kids and every summer after dinner we played endless games of hide and seek, using the streetlight on the boulevard outside my house as home base. Eventually twilight set in, the streetlight would come on, and the kids would drift away until the next day. It was magical).
Kick the Can
Capture the Flag
Tag - Freeze tag was a favourite, but there are lots of versions
British Bulldog
Red Rover - personally, I hated this game, but I know lots of people love it (Two lines of children face each other, and one line will chant "Red rover, red rover we call _____ over, and that kid has to try to run through the linked hands of the chanters)
Hop Scotch
Jump rope games
Storytelling/pretend games - explorers of strange lands, detectives, archeologists.....
My kids loved scavenger hunts, but they take some planning and effort, so we usually reserved them for special occasions.
