I have always loved playing Tetris on my classic Nintendo, so this is pretty good news.

Research has shown that playing the game can improve your brain's efficiency and will thicken some areas of the cortex.

Three months of Tetris playing had two distinct effects on the brains of research subjects: Some areas in the brain showed greater efficiency (the blue areas in the diagram above), and different areas showed thicker cortexes, which is a sign of more grey matter (red). This, says the doctors who undertook the study, shows that focusing on a "challenging visuospatial task" like a videogame can actually alter the structure of the brain, not just increase brain activity [Wired.com]. But surprisingly, there was no overlap between the regions that became more efficient and those that thickened. Haier says more research must be done to determine how different areas of the brain interact during game playing.

Source: Discover Magazine