They can all be played alone in theory, but try to get a friend or two to participate. Two or more minds interacting helps you generate more ideas gets you thinking in new directions. By the way, these produce no clear "winners," so they're not truly competitive games, but they are fun - and good for the brain.

You can do this simple exercise in imagination anywhere. Invents a survival situation, like a plane crash in the mountains or a boat lost in the ocean. Make up some details like time of year, weather, and maybe specify no rescue for a month. Player then consider only what they are wearing or carrying at the moment, and try to think of ways to use each item in that survival situation (along with whatever things can be reasonably assumed to be part of the scenario).

Try for the most original and plausible ideas. For example, a paper clip could be a fish hook, or a needle for sewing together warm clothing from airplane seat material. A hat could be used for cooking by filling it with water and dropping heated stones into it until it boils. A straw for drinking from coconuts could be made from a pen.

For an alternate version, you can choose just one object at a time from any in the room. Then everyone can try to think of uses for it in the given survival scenario. Either way, this is a real exercise of one's imagination and creativity.

For this one, you and a friend start with something about which you disagree. It could be in the area of politics, philosophy, law, economics, or about any issue that is complex enough for reasonable people to have differing positions. Then you each try to make the best case you can for the other person's position, and see who has the best argument. Another way to play this is to find any issue that you agree on, and both take the opposing view, to see what kind of ideas you each have.

This little debating game can change how you think about an issue. Once you effectively argue for anything, it's very easy to start believing some of what you say. It demonstrates how powerful your mind is. When it adopts a given perspective, it can usually make sense of it quickly and defend it easily. That makes this exercise a warning as well. It suggests we can convince ourselves of almost anything, so perhaps our current thinking isn't as rational as we like to think.

Trying to invent jokes can really get you thinking, and possibly laughing, but it can also be very frustrating. For this game, have someone choose any object in the room (or car, if you are driving). Players then try to come up with a joke or two about the object or involving it in some way. A reasonable time limit is perhaps five minutes. See who can create the funniest joke in that time.

Trying to create something funny is more difficult than it might seem. It will really exercise your lateral thinking abilities above all. I just chose the calendar on my wall as my random object, to give an example. A few minutes later, this is all I could come up with:

Bob, my friend, was tired of winter, so he tore January out of the calendar and pasted July in its place. The next week I asked him how this was working out for him. He sighed and told me "I just can't get a break it seems. I mean, who would have thought it would snow on the fourth of July!" (My other one was about a guy who fell in love with the girl on the calendar because he could always get a date with her.)

Creating truly funny jokes is tough, but it will get you thinking, perhaps even more than the other games here. For an alternative you could start with ideas or issues instead of objects, or you could specify that players have to create a funny riddle. And by the way, if you learn a few humor "algorithms," this process gets easier.