Discontinuous Galerkin FEM

The Summer School on Advances in Finite Element Methods will be held in Cape Town, South Africa, from 14-18 Jan 2013.
The website www.fesummerschool.co.za contains details such as registration, accommodation, lecturers and the schedule. 

The objective of this summer school is first, to provide the necessary background in the mathematics of finite elements, and second, to build on this background by addressing the topics of adaptivity and discontinuous Galerkin methods.

Can some of you recommend a source to learn about Discontinuous Galerkin FEM?? I am specifically interested in its application in geomechanics but I need to learn the basics first!