Brain Workshop is a free open-source version of the Dual N-Back mental exercise
A recent study published in PNAS, an important scientific journal, shows that a particular memory task called Dual N-Back may actually improve working memory (short term memory) and fluid intelligence. This finding is important because fluid intelligence was previously thought to be unchangeable. The game involves remembering a sequence of spoken letters and a sequence of positions of a square at the same time.
Anecdotal evidence suggests that the dual n-back task also enhances focus and attention and may help improve the symptoms of ADHD/ADD.
In addition to its ability to closely replicate the conditions of the original study by Jaeggi et al. (2008), Brain Workshop includes optional extended game modes such as Triple N-Back and Arithmetic N-Back. It also includes features such as statistics tracking, graphs and easy configurability.