Coding. Essentially, time spend in a text editor / browser window combo, developing new features and new products. Recently I've been working on mobile apps so there is also a bunch of testing on the device as needed. I personally use gedit but our developers use whatever OS and text editor they find most productive. Bunch of people here like SublimeText. Chrome is universal, though we test on other browsers when appropriate.

Your language breakdown really depends on the job and the project. If I'm working on a web app, I do about 50% PHP and 50% "frontend" (i.e. HTML / CSS / LESS / Javascript / Backbone / jQuery etc.). If I'm working on a mobile app, since we don't have a serverside language available, the frontend work shifts up (and any heavy processing / database usage we need ends up as an API on our server). There's also some Node.js sprinkled in there for worker scripts and queue processors.