15 Jun 2012
Unfortunately, I waited with the updates of the Github API client until they ultimately killed API v2 earlier this week. Since this is required to fetch your data after successfully signing in to the Toolbox via OAuth, you currently won't be able to sign in to the Toolbox via Github.
I have the fix in the pipes and should manage to finish and roll it out within the next 32 hours or so.
Sorry for the inconvenience!
By the way, if you want to keep updated on current Toolbox news you may want to follow @rubytoolbox on Twitter.
Update 13:25 UTC: Existing users should be able to log in again. If you are trying to get sign in for the first time, it might fail, but I'm on it :)