Optical Illusions
Optical illusions have long been popular, both as art and a way to keep the brain active. There are many different types of optical illusions , from the simplest of photo-editing tricks to the more intense "magic eye" pictures, which cause you to stare and fully concentrate to see a picture within a picture. If you're looking for some good optical illusions to keep the mind active, search the Internet for "anomalous motion pictures," "3D/2D illusion" and "magic motion".
Riddles
Riddles are a popular choice when you need a simple mind activity for the entire family. From the simplest riddles for kids all the way up to tricky twisters for adults, there are both traditional and new riddles to try.
A few examples to try on for size are:
What walks all day on its head? (A nail on a horseshoe)
What gets wet when drying? (A towel)
The more you take, the more you leave behind. What are they? (Footprints)
These are just a few ideas from riddles that can be found everywhere, from the stick of a popsicle to a book at your local library. Try different themes or levels of difficulty to get everyone involved around the dinner table or on the road.
Video Games
Mind games don't end on the Internet or in the bookstore. You can also enjoy mind games on handheld video game devices that are travel-friendly and bulk-free. On an airplane, where space is extremely limited, a mind game designed for your Sony, Nintendo or even a smart phone is agood choice. For the Sony PSP, check out Hot Brain -- a game that tests your brain in various areas, including logic, memory, math, language and levels of concentration. For the Nintendo DS, try Brain Age, which trains your brain to be at its peak performance through math, logic and reading aloud. Multiple mind-enhancing games, including Sudoku, PuzzleManiak and Wiki Hunt, are available for smart phones.
Design Your Own
If you don't feel challenged enough (or perhaps too challenged) by the various mind games and riddles found online and in your local stores, consider creating your own. Design a maze or puzzle on your own or through the help of an online tutorial or design platform. Then you can amaze your family and friends with what you've created. Stump each other or reign supreme as the brain-teasing champ of the clan.