The X.Org Foundation has been accepted this year by Google as a Summer of Code organization so interested student developers can contribute to the X.Org Server, Mesa, Wayland, and related projects while being paid for their summer work.
Google announced the GSoC 2014
organizations and this year the X.Org Foundation is on the list (some times in the past they haven't been). Hopefully some very motivated students will decide to join the Google Summer of Code to get involved with X.Org/Mesa/Wayland development while benefiting financially from their summer work and end up becoming long-time contributors to the stack.
There is the X.Org Wiki GSoC Ideas page
with a list of potential projects. Among the 2014 ideas are Glamor performance tuning, Mesa GLSL compiler optimizations and other shader compiler improvements, OpenCL image support for the R600g/RadeonSI drivers, Clover OpenCL state tracker improvements, Piglit OpenGL 4.x regression tests, Shatter support in the X.Org Server to replace Xinerama, and working on Xpra.
Martin Peres shared the X.Org GSoC 2014 news in a mailing list post
. For student developers that might not make it into GSoC, the X.Org Foundation also runs the less-advertised Endless Vacation of Code