tDCS

transcranial direct current stimulation (tDCS) is the application of very weak electrical currents (1-2 mA) to modulate the activity of neurons in the brain. (Wikipedia)

I was right!!!
I at least suspected it. Well, I just liked the idea of doing something where I got to hide in my basement and put electrodes on my head. I'm not crazy, but I like the thought of it. I mean have you seen all the "normal" fuckers out there? With their pent up neurosis, their constant chasing the elusive image of the American Dream® (and I use image quite deliberately), all bundled up in a warm, fuzzy blanket of false security brought to you by the folks at Haliburton.
But I digress. This is great...the idea of sending electricity through your head isn't necessarily bad for you, in fact it might even be good for you.
I'm just pissed I got beat on the story.

Brain-O-Matic
By PAGAN KENNEDY
February 7, 2007
Can a jolt from a nine-volt battery make you smarter? Happier? Medical researchers revive a discarded technology and set the stage for the ‘brain pod’. (More...)

Here's some discussion at Make about tDCS with a link to a podcast.

More screwing around with your own head
Along these lines, one device I've tried and I like is the Brainwave Generator which operates aurally. I had a headache for a couple of days. Not a rager, but it was incessant. I downloaded the software, put on the head phones, and set it to Headache treatment (circular). Ten minutes, the headache was gone.
The concept behind it is entrainment or brainwave entrainment, which is to put it simply, the natural tendency for frequencies to want to agree. Now certain overall states of the brain produce a certain overall frequency, which many of us have heard of as Alpha, Beta, Delta, or Theta wave states.
Now should you be in a state that you don't like, such as Alpha when you're trying to get to sleep (the deepest sleep state being Theta), you place your headphones on, select the preset you want (Sleep) and let the program walk your brainwaves down to lower frequencies with not unpleasant tones.
This process is essentially what one does using other techniques such a meditation or biofeedback, except that one doesn't have to spend a lot of time practicing until one learns who to adjust themselves. With the software, one frequency or the other has a tendency to want to give. The programs aren't responsive, which leaves your brain as the one to have to adjust.
It all made a lot of sense to me. I've used it on and off for a couple of years now and found the effects top be subtle but noticeable. Nothing was as profound as the headache treatment, but I particularly like to use the relaxation or meditation settings as I run. I figure that exercise is meant to calm and relax and if I associate those qualities with the activity it'll make the activity all the more desirable. I usually adjust the volume settings on the program so I can play it under music or a podcast as I workout.
The program is free, but after a month you'll get a ten second nag. Paying for it also unlocks forums where people discuss their experiences and discoveries as they try different settings. There are also other programs/devices out there which I haven't tried, but look promising. Search around a bit.
The point is that there are more ways than just the digestive system (eg. caffeine) to hack your brain.

• Brainwave Generator