What is OSR?

OSR stands for the following (depending on who you talk to).
Old School Rules
Old School Renaissance
Old School Revival

As far as what it actually is, there's a variety of opinions.  First and foremost it is a mindset, secondly its using old rules for role playing games (in some cases simpler, some cases not).  These rules don't just encompass Dungeons & Dragons, but a lot of other games as well.

If you are new to this whole OSR thing, there are a lot of wonderful resources out there.  These 2 books are great resources.

Books
A Quick Old School Primer By Matthew J. Finch.

The Role Playing Game By Chris Gonnerman

Games
There are a variety of different games that are Old School or Old School influenced.  A taste of them can be found below.


Community

Blogs