What can I say that hasn't been said? I grew up with a Nintendo, and the minute I started playing I was hooked. Matching dropping, building, combo tetrises.... My eyes glaze just thinking about playing.
Tetris is a must have for anyone of any age. It tests hand and eye coordination, colorblindness, and tolerance for sitting for long periods of time.
Give this game two minutes, and be sure it will suck you in completely. Have fun, and watch out for your thumbs, they're your best friends here.