Kelly Hodgkins shares a technique to "make yourself smarter in 20 days":
University of Michigan psychologist John Jonides shows that you can use n-back mental training exercises to increase your intelligence. N-back exercises require you to remember how far back you saw a symbol or heard a noise in a series. It is a way of measuring fluid intelligence which governs how you think abstractly, reason and solve problems. This part of your intelligence begins to decline when you hit your 30s or 40s. Oh noes.
All is not lost as Jonides' research team found that 20 minutes of n-back training a day for 20 days can improve your fluid intelligence for up to three months. You don't have to see a shrink to train, just grab your smartphone and search the app store for n-back exercises. There are also desktop apps as well.