[amyjess]

I can't think of any where you can't view it, but there are several licenses that allow you to view but not modify.

Microsoft is in the habit of letting development partners view their source but not publish or modify it, and then there's software like UW Pico that have licenses that allow viewing by the general public but not modification.

[Guvante]

Microsoft is certainly not the only one who did this. Many business to business deals involve read only access to source code (usually by platform providers).