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.
The final company, www.brainbuilder.com, $7.95 per month, $49.95 per year, also offers a variety of interactive cognitive testing and training programs, along with the ability to track your progress. The free sample test is more involved, and difficult.
A recent study by the Wall Street Journal (subscription required) rated all three services as very close on ease of use and clarity of instructions. Happy Neuron and My Brain Trainer rated higher in fun.
Given the price difference, I'd recommend starting with My Brain Trainer. Or do what I do; buy old math textbooks for a buck or two at the thrift store and work a few problems a day.
And keep reading WalletPop. We'll try to stretch your mind a bit!