I have recently been following the SCENEBLOCK gang, and have really enjoyed their work and projects. Recently they shared a great little DIY project to improve the quality of the tiny built in mics on Canon DSLRs. I am definitely going to give this a shot and would like to see how well it performs in several different sound environments.
Check out this video showing some results of the muff being attached, then check out the guide.
Link to Guide: DIY 5D Mark II Windmuff
(Via SCENE BLOCK)