Add up the alphabet
Give the different letters of the alphabet the numerical values 1–26 (A=1, B=2, etc.). Try to think of words in which the sum of the letters is 40 (or 45, 50 etc). Only math geeks can figure out this crazy numbers riddle. Can you?
Study the phone bill
Take a look at your phone bill and try to recall to whom each phone call was made. If you rely on your cell-phone full-time now, look back at your recent call log and try to remember what you and the other person spoke about.
Mess with your mouse
Flip your computer mouse, so that moving the ball left and up makes the cursor move right and down. Or, work your non-dominant hand by plugging the mouse into the opposite side of the computer.
Try to recall the names of teachers or fellow students in your class at school. See if you can remember details such as what they wore or what kind of person they were. Next time, think about a past workplace or a street where you once lived. You will be surprised at how much you can remember.
Read upside down
Turn a book or a newspaper upside down. Read the page from the bottom to the top. Notice how much more effort is needed to make sense of the structure of sentences. Can you find the missing word in this tricky brain teaser?
Test your vocab
Write down as many words as you can starting with a certain letter of the alphabet in 2 minutes. Try letters such as M, T, and C or challenge yourself with O or Y.
Concentrate on the second hand of a watch or clock for 1 minute. Now close your eyes and see if you can time a minute exactly. You might be surprised how off you are.
Take a new route
LMproduction/ShutterstockDriving, running, or biking the same way every day allows your brain to go on autopilot. Stimulate your mind by trying a new route. You'll have to visualize the roads in your head, which activates to cortex and the hippocampus.
Memorize a picture
mimagephotography/shutterstockLook at a photo online and try to remember everything that appears in it. Cover the photo and list those things. Now look at the photo again and see how many you got correct. For example, can you find the robin hidden in this photo?
Eat with chopsticks
Stasique/ShutterstockSimilar to switching up your computer mouse, this one forces you to slow down and take in what's happening. As a bonus, doing this will help you savor your food even more. An MIT professor called this "the hardest puzzle ever." Can you solve it?