Brain training sounds like a mundane exercise, but a steady wave of sites and apps wants us to think of those words as anything but (we all know about this one). Each promises that you can improve your mental capacity in some way through a combination of puzzles and games.

Peak fits into this mold. The bright and colorful app has attracted a significant following over on Apple's mobile platform since its launch in September, with millions of downloads spread across two dozen countries. Now the experience is coming to Android.

The app tries to improve your focus, language skills, problem solving capability, and something called mental agility. It does so through a series of games, which you play every few days in order to keep your brain from falling out, or something of the sort. Some of the challenges are word puzzles (one of them I swear I've seen before), while others may feel more akin to Tetris or Minesweeper. The app lets you track your performance and see how your brain works in the form of a chart.

Peak is free to download, but to get all of the features—such as the full selection of games, personalized goals and training, and advanced statistics—you need to subscribe. Your options are $4.50 a month or $36.88 a year. Payments are handled through Google Play.

The free version limits you to four games per day, and it doesn't offer the detailed statistics you can expect from the pro version. But if your response to that is a "meh" with a shrug, then by all means, enjoy training your brain without paying a dime.