Gitlab is a combination of Git, Gitolite and some abilities on managing projects, users, issues, and requests,...

In brief, below are things you could do with (and like):

• Create git repositories via administrator dashboard, that is called project in Gitlab
• Manage users, contact information, user public keys, participated projects,...
• Having issue workflow for tracking
• Visually show the branches, pushes, merges,...
• Nice and GitHub-like UI style, users can have there own selection (only two themes at the moment)
• Snippets sharing between team members
• Wiki, files,...

Just a few cons:

• Really tricky and time consuming to someone with RHEL, CentOS, Fedora,.. and newbie to Ruby on Rails.
• The most awkward thing possibly is request for manually push to repository after creating it.

So, if you want to give a try, just checking out some guides here: https://github.com/gitlabhq/gitlabhq/wiki

Some notices to the RHEL, CentOS users: Some required default packages of the system are really old to work with this, even with the lastest distro version. So, you should remove and install from source some packages: ruby, gems,... and additionally yum some others following this guide (top of the page):  https://gist.github.com/1601228