Jorge Rance has created a surveillance system to monitor an injured bird he rescued which tweets when different aspects of the environment need tweaking (e.g. a water level monitor). The Foundation just featured it on their front page (so hopefully his site will withstand the barrage of hits now headed his way).
He’s written a full tutorial on how to replicate his project and all the code has been released as open source so you can monitor your own pet!
I’m really hoping that schools pick this up to monitor classroom pets!