GitHub allows other people (or fake accounts, spam bots etc) to add you as a collaborateur to a repo without any approval by yourself. This leads to annoying long repo list full of semi-spam (unknown people add me to their projects, GitHub handles these projects like my own repos), very very unhandy when working on/with GitHub 9hrs a day.
Is there a way to remove yourself from projects that "added" you ?
You should check this out https://help.github.com/articles/removing-yourself-from-a-collaborator-s-repository/
As it says there:
In the user bar in the top-right corner of any page, click the gear
In the left sidebar, click Repositories.
Next to the repository you want to leave, click Leave.
click "I understand, leave this repository"
Hope it helps!