The New Addiction: Elite Beat Agents 

So, back before Christmas, Brett had been singing the praises of this little Nintendo DS game called Elite Beat Agents. He described the game exactly as it was: "you tap the screen to the beat of songs and you help these guys like cheer on people to solve ridiculous problems." To which I replied (paraphrased): "Ummm, no thanks. You smell like fish."
Then I tried the game.

And the little light bulb went off in my head. I got it. It all made perfect sense.

Elite Beat Agents is the most fun game I've played in, I don't know, forever. Basically, it's Guitar Hero for the Nintendo DS. The game sets up these little scenarios, like say, two "socialites" getting stranded on a deserted island. Then the "Material Girl" by Madonna starts playing, and you tap along to the beat, hitting these little circles in order, occasionally dragging a circle back and forth over a path. If you tap along in time, you win. If you don't, you lose.

You hear someone describe it, you think it sounds ridiculous. You see someone play it, you get a little intrigued. You play it, you're hooked.

It's one of those games where you get frustrated because you can't get by a song (let's say, "Canned Heat" by Jamiroquai, since that's the one that kicks my arse), but you keep trying, since you get a little further each time. On your 5th try, you finally pick up the beat and you breeze through.

Everything about the game is silly. The song selection ("Sk8er Boi", "YMCA", "Material Girl", "You're the Inspiration"). The scenarios are silly, except one about a girl who's dad DIED and his ghost brings her a teddy bear, which is sooooo out of place in the game that it's awesome.

I can't do it justice. This game is astounding. A Technorati search turned up 4000+ mentions of the game.

You won't understand it until you try it, but to get an idea, check out this YouTube video of the "September" level.