Test your recall. Make a list — grocery items, things to do, or anything else that comes to mind — and memorize it. An hour or so later, see how many items you can recall. Make the list as challenging as possible for the greatest mental stimulation.
Do math in your head. Figure out problems without the aid of a pencil, paper, or computer. You can make this more difficult — and athletic — by walking at the same time.
Take a cooking class. Learn how to cook a new cuisine. Cooking uses a number of senses — smell, touch, sight, and taste — which involve different parts of the brain.
Learn a foreign language. The listening and hearing involved stimulates the brain. What’s more, a rich vocabulary has been linked to a reduced risk for cognitive decline, according to a Spanish study published in October 2014 in the journal Annals of Psychology.
Create word pictures. Visualize the spelling of a word in your head, and then try to think of other words that begin (or end) with the same two letters.
Draw a map from memory. After returning home from visiting a new place, try to draw a map of the area. Repeat this exercise each time you go somewhere new.
Challenge your taste buds. When eating, try to identify individual ingredients in your meal, including subtle herbs and spices.
Refine your hand-eye coordination. Take up a new hobby that involves fine motor skills, such as knitting, drawing, painting, or assembling a puzzle.