If you have cable, browse YouTube, enjoy Hulu, or partake in any activity that involves viewing video ads, there's a solid chance you've seen a Lumosity ad. But on the off chance that you haven't, here's one (and you thought browsing a blog would keep you safe).
Lumosity is a service that promises to train your brain in areas related to memory, speed, attentiveness, problem solving, and others. The website launched in 2007 and has millions of members, but many users come via a mobile app that has, thus far, only been available for iOS. Now that has changed. The Lumosity app has come to Android, complete with mobile brain teasers and other bite-sized mental exercises.
Lumosity creates a brain workout for you each day based on the areas you're most interested in improving. Each of these daily routines consists of five games and should take fifteen minutes total.
The Play Store page mentions in-app purchases, but these refer to the ability to subscribe for Lumosity Premium, something you will need to do to unlock full access to the service. A month of use goes for $11.95, whereas a full year goes for the significantly cheaper rate of $59.95. Assuming you plan on sticking around that long, that latter option may just be worth a look.