It's definitely annoying when you are trying to find the "canonical" fork of a project on Github, but it's not THAT hard to just look under the project name and click on the "forked from xyz/project" link (projects rarely go more than a couple of forks deep), or in the worst case click on the network tab and look at the tree. Edit: If it's a Ruby Gem, you can also look up the gem on rubygems.org and click the Homepag…
That's not the only problem.
Even with the network tree, you're still screwed, because Github's network graphs are incomplete. Take this brief conversation from ruby-talk last year:
http://www.ruby-forum.com/topic/203100
I challenge you to deduce the result of that discussion from the information available here: https://github.com/rightscale/right_aws/network
Right now, without delving into the code, I still can't tell which one is supposed to be canonical, if they've diverged irreparably, or if it just doesn't matter which I pick.