Vanilla 1 is no longer supported or maintained. If you need a copy, you can get it here
While we've been hard at work getting Vanilla 2 ready for it's official release, others in the community have been hard at work fixing lingering bugs and adding feature refinements to Vanilla 1. Vanilla 1.1.10 is now available. The main changes in this release are replacement of deprecated functions, and updates to Scriptaculous and Prototype.
You can find upgrade instructions here:http://code.google.com/p/lussumo-vanilla/wiki/VanillaUpgrading
And you can download it here:http://vanillaforums.org/download