It used to be so damn simple. You had GPL, LGPL and BSD/MIT.
Now all the corporations have gotten into free software and open source, rather than just saying "hey, we use GPL/LGPL/BSD" and making the lives of users simple, every company now has to create their own version of at least GPL and BSD. And then they come up with "Shared Source" licenses and a few other knock-offs which sound like they are a standard FOSS licence but aren't.
On this page, as I find myself sucked into the painful existence that is software licenses, I shall document them.
Microsoft Public License
It's like a BSD/MIT license but if you make a derivative you must include the Ms-PL license text and comply with the stuff about patents/trademarks.
Example: IronRuby