TortoiseSVN - The coolest interface to (Sub)version control
VisualSVN Server - Get an easy to use Subversion (SVN) server for Windows. It works out-of-the-box and is suitable both for small business and enterprises. Available for free!
RapidSVN - CollabNet, Facilitating Collaborative Software Development
Subversion Edge - What is Subversion Edge? A certified software stack containing the latest versions
SnailSVN - Similar to Tortoise SVN for Windows but integrated into Finder
GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.