Plants Vs Zombies

THAT ZOMBIE IS POLE VAULTING! OH THE HUMANITY!

Plants Vs Zombies is a very silly name and concept that happens to be attached to a very addicting and consuming game.
You assume the role of a homeowner whose house is under siege from an army of zombies, armed with screen doors, parking cones, pole vaults, and their bare, festering hands. Your only defense are an array of bizarre plants you can grow on your yard, in your swimming pool, on your roof, that will eat, explode, freeze, burn, and otherwise annihilate the walking dead.

It plays more or less like a standard tower defense game- if that sounds like gibberish to you, it's simply a kind of game where you have to 'defend' a certain point using 'towers'- fixed objects that you place down.

What makes it hard is the varied, creative, and overwhelmingly cute nature of the opposition, and what makes it addictive is the challenging and well-thought out levels and the constant quest for the best strategy as you mix and match your plants to discover what ends in glorious victory, and what ends with you getting your brains scooped out of your head. Lovingly.

I haven't beaten it, but I did get to play the demo over at Popcap.com, and then subsequently spend some time with the full version. It's every bit as addictive as one would guess given its massive popularity, and though it starts off a little slow, when I skipped ahead I was roundly trounced a few times and impressed by the depth it seems to show off at the later levels.