Comrade Hobbes forwarded Last Stand to me. Webgame shooter thing based around an almost Tower Defence-esque mechanic. By night, you and your team defend the barricades against zombies. By day, you allocate how many hours you want to spent either repairing the barricade, searching for weapons or looking for survivors. It repeats over 20 nights. It's unlikely you'll play it twice, but you'll be happy to play it once.
And, in my experience, Valentines Day is best started with a headshot. Get shooting.