A good game to play with children to pass the time. Doesn't have to be children though. It goes like this:

I spy... with my little eye... something that is <insert colour here>.

The child then has to try to guess what you see. If there's more than one kid, the kids take turns answering, and the first one to guess correctly wins. This game helps kids sort stuff by colour and become more observant of their environment. Then they get to ask you.

Some children aren't that good at picking objects for this game. Some will pick things that are way too obvious, or that have already been picked. And sometimes kids pick objects that are way too obscure or aren't the right colour. Some kids forget what they picked or answer yes to whatever answer you give.

You can play variations of I Spy with your peers. For example:

I spy... with my little eye... someone in CS.
I hear... with my little ear... a song that sucks.