Lumosity is a leader in online brain training. This neuroscience research company is based in San Francisco. Lumosity offers a brain training program consisting of more than 40 games in the areas of memory, attention, flexibility, processing speed and problem-solving.

“Lumosity itself has grown by 150 percent year-on-year since its launch in 2005 and now reaches more than 35 million people worldwide,” said Elizabeth Day of The Guardian. “They are big business.”

Games are available in numerous languages, including English, Spanish and German.

Other popular sites are Jungle Memory, Nintendo and CogniFit, developing a wide range of user-friendly neuroscientific puzzles.

Most Popular Games

There are a lot of great sources. From the National Geographic to the AARP to leading Lumosity, there is a wide variety from which to choose.

Lumosity-Word Bubbles

Word Bubbles is the most popular game on Lumosity. Released in 2007, it has a goal of verbal flexibility.

When you start the game, three letters are displayed. You must write words that start with these three letters and cannot use the same word twice. Each word you write advances the bubble, which contains the number of letters. Therefore, if you write "snare," the bubble with the number 5 in it will move up. Any bubble that moves above the surface of the water becomes a star and earns you additional points.

National Geographic

The National Geographic Channel hosts a show called Brain Games on Monday nights at 9:00 p.m. EST.

Their description: "Hosted by 'wonder junkie' Jason Silva, Brain Games sizes up the ultimate super-computer -- the human brain -- using an intricate string of mind-boggling experiments, optical illusions, brainteasers and hard science. With man-on-the-street demonstrations and viewer participation through interactive brain-busters, National Geographic Channel's hit series offers a workout for your mind."