Subversion repository
BAScript source code is maintained in a Subversion (SVN) repository.
There are clients for almost any platform. You can also browse it.
To get the current WIP version, use the next command:
svn co svn://svn.code.sf.net/p/bascript/code/trunk bascript
Note that only developers can commit new content to the SVN.
To get older versions, look at the releases subdirectory:
svn co svn://svn.code.sf.net/p/bascript/code/releases/<version-num> bascript
Where <version-num> is the version you're looking for (eg: 2.2.0 etc). You can find those at the downloads page also.
You can get the WIP unstable version 3 using the next command:
svn co svn://svn.code.sf.net/p/bascript/code/branches/3.0 bascript.3