Scratch

Moderate...
In the userpage, there could be a Moderate button which the leader can moderate which projects are his/her favorite ones and the rest go to the archives or to the creator's userpage where they can remix then!

Work in Progress...
The projects that were somewhat made could go into the 'Work in Progress' section, which the rest of the people could download the project and work on it, which the leader could moderate like up above and the rest...as said...could go to the creator's page!

Public or Invite Only...
The team leader could make the team public or invite only, which is good for companies! The 'Invite Only' feature would be good for private groups and the 'Public' feature would mean that anyone can join!

Transfer Project from Userpage...
The person who is uploading the project could first upload it to his or her account, then transfer the project from their own userpage to the team's userpage, making it so that it is not hard to get a project to the team userpage.

Mockup of Scratch Userpage...not that good...