Some services can be configured to GET or POST to a URL of your choosing when something happens. E.g. you can ask Github to "GET http://my-site.org/action/ http

Some services can be configured to GET or POST to a URL of your choosing when something happens. E.g. you can ask Github to "GET http://my-site.org/action/ http://my-site.org/action/ whenever you push commits to your repositories. If you control my-site.org, you can have the /action/ script do whatever you like. These "push" notifications are super- simple, reasonably low latency, and don't require polling. I did something similar when taking an operating systems class. Linux kernel compiles take quite a long time, so I set up my site to send me a text message when I "GET /compile-done." Then, a quick "make ; curl http://my-site/compile-done http://my-site/compile-done would drop me a text message and I could get a sandwich or something until it was done.