Here are two simple games to play with young children when it is too hot out to be very active.

I Spy – To play this game simply choose an object within eyeshot and state the color of the object (or with older children say the first letter that the name of the object begins with). For example, if your object is a banana you say “I spy with my little eye, something yellow (or beginning with ‘B’)” Each person takes turns guessing what object you spied. Whoever guesses the object gets to go next.

Hide It – Hide an object in an obvious place. For example, place your portable telephone on top of the television. The first person to find the telephone gets to pick the next object and hide it. The only rule is that the object cannot actually be “hidden”, it must be in a visible place and not hidden from view.

http://www.ehow.com/list_6718041_easy-play-kids-inside-outside.html