As we boomers enter our 'golden years' (explain to me what's so 'golden' about stiff knees and Rastafarian-length nose hairs?) a new industry has emerged to help us address our fear of losing our mental faculties; brain fitness. Exercises designed to work out our brains are offered in devices, software, or as on-line subscriptions. I took a look at three sites offering to help pump up your cortex and keep the corpse out of your corpus callosum.
http://www.mybraintrainer.com/, $9.95 for three months, $29.95 for a year. This site provides daily 10 -20 minute workouts, along with an online brain diary (Dear Diary; today I thought, and thought some more, then I acted instinctively, then I shut down to watch television). It offers a free sample test, on which I scored depressingly poorly.
http://www.happy-neuron.com/, $9.95 per month, $99.95 per year, claims to have more than 3000 hours of brain-buffing programming to offer its members, as well as an online tracker of their progress (or regress, I suppose). Unfortunately, its version of a free trial is what I consider a scam; you sign up with a credit card for the free trial, and you must then take the time to discontinue your membership or they will start billing your account monthly. I'd steer clear of such a deal.