In case it wasn't so obvious before, the Sydney Morning Herald would like to inform you that strapping a device to your head with the intent of hitting your brain with a surge of electricity is probably a bad idea. We can tell you that it's definitely stupid.
The quick article makes no mention of brand, but the headset is en route and is targeted at gamers. It's probably not difficult to guess why - "Overclock your brain using transcranial Direct Current Stimulation to increase the plasticity of your brain. Make your synapses fire faster."
Sheesh, the fact that such a device exists at all is a bit foolish. Gamers have been known to go great lengths to improve their technique and performance, but most settle on a different set of peripherals, not messing with their body. While this device very-well could cause no damage, the long-term side-effects are unknown, though similar medical procedures are used to treat depression. However, that's of course under the guidance of a doctor - the user simply doesn't take it upon themselves to buy an off-the-shelf device and try their luck.
Professor Colleen Loo from the University of New South Wales put it well; "It's a bit like having an accelerator and brake in a car, neither is bad and both are very useful but applying them judiciously at the right time and in the right context is absolutely essential. I think stimulation of yourself with do-it-yourself kits is potentially quite dangerous."
How much would it cost to potentially screw yourself up with this device? A mere $249. Almost seems like a steal.