Exceptions have been a mainstay of copyleft licensing since the creation of the GPL. They are an essential part of the copyleft licensing system, and provide a license-proliferation-free method for developers to chose precise terms for situations that may not be accounted for in the standard licenses. This talk introduces the general idea of GPL exceptions and how they work to carve out the spectrum of licensing between the GPL, LGPL, and the highly permissive licenses. As a case study, the talk will cover in detail the GCC Runtime Library Exception released this year. Attendees can expect to gain a general understanding of why GPL exceptions are written, how exceptions work under GPLv2 and GPLv3, and how they can be used when none of the usual licenses fit the task. There will be some technical concepts, but the talk will likely intrigue to both developers and businesspeople.