For the people eager to play with the latest state of development, two things are provided:
regular dev builds
source code SVN repository
Development builds are created once per a few weeks from the current trunk.
They can be obtained via tdm_installer.
Just run the installer, check "Get Custom Version" on the first page, then select proper version in "dev" folder on the second page.
Name of any dev version looks like devXXXXX-YYYY, where XXXXX and YYYY are SVN