Robber Plants: Farm Fortress
Given that the RPS servers wobble like a tightrope walker whenever Notch tips his hat towards us on Twitter, I'm amazed Farm Fortress is still standing. But it is, and it means I can point you in the same direction that the benevolent Minecraft creator pointed. Join the orderly queue. It looks rather interesting. A browser-based persistent, top-down farming and fortress making game. Why farms? Because in this post-apocalyptic vision of future awfulness, the only job for an ex-con is high-risk illegal farming. Why fortresses? Hello! Post-apocalyptic farming obviously means you're fighting off mutants, other players (a truly apocalyptic addition), and corporate robots. Best build them walls and get hoe-ing in the open alpha.
So the walls go up and the plants are planted. The persistence is what I'm really intrigued by: you set defenses to protect your farm as the world carries on when you're offline. You can team up with others to build a mega farm, but people can attack the base at any time and you'll need to build competent protection that'll keep your plants unharvested by the rotters when you're not around. There are e-mail settings to warn you when your land is being attacked. The fighting is quick and a bit simplistic, but I imagine the joy in it is in perfection the farm.
While it's free-to-play, you can purchase benefits: when you're out of lives, you can't play for 12 hours, but you can buy more lives and/or a 6 hour resurrection. You can also purchase land plots, if you're particularly horticulturally inclined. The open alpha is still a bit broken: it just sort of vanished for me, so it might be worth having some serious time with the free component before laying down some cabbage.