Cyber-Dojo is where software teams do deliberate practice.
You write your code and tests inside a browser!
A Cyber-Dojo session is great for learning about tdd, team dynamics, and software development in general.
A live online Cyber-Dojo coding dojo server lives at http://cyber-dojo.com.
You can also build your own server. Simply install VirtualBox and download the TurnKey Linux Cyber-Dojo server image.
Read the readme.txt file for the details.