Budding Android developers looking to submerge their coding digits right this second should point their browsers at Programr, where you can not only cook up Android apps without leaving the comfort of Chrome, Firefox, etcetera, but download them in phone-ready form, making it a cinch to share them with friends or test them on your own hardware.
Being able to type and compile Java in a browser isn't anything new, but downloading that code into an Android-compatible APK to install directly onto your phone? That's very shiny.
This functionality is a new addition to Programr's repertoire, which already support C#, Ruby, Python and Perl, among other languages.
Coding is done by typing into a window that replicates a typical integrated development environment. The individual code files for your project are managed on the left, while typing is done though the right-hand window. The left-hand section also contains buttons to compile, run and download your work.
It should be noted some of the supported languages don't do much other than write out results to a console, so you won't be doing anything that graphical via C#, for instance. However, the site can handle visuals for Android apps.
I'm going to post-posthumously stress the word "budding" from my open paragraph -- this is not the place to do serious development. IDEs such as MonoDevelop, Visual Studio and Eclipse offer more powerful options and capabilities and any project you plan to spend more than a week or so on probably warrants some sort of source control. The site itself can also be flaky; I've seen it fail to load the IDE a few times and I had trouble running some of the available user projects.
These issues aside, if you want to practise a few code snippets or get a rough idea of a particular language's learning curve, you could do worse than Programr.