What software is good for exercising brain functions? I know of brain fitness by Posit. Any other ones?

I haven't been to school since I finished college more than 15 years ago. My job has become a monotonous routine. Recently, I've been reading about the capacity of the brain to create new connections between neurons by 'exercising' it. I'd like to find good software for doing just that. I know of brain fitness by posit, brain fitness by happy-neuron.com. I haven't purchased either one of those because I'd like to know what other options I have.