Magic Lantern is an unofficial firmware update to the Canon 5D Mark II that enables a variety of wanted features for videography.
The firmware enables features such as: Manual audio gain (as opposed to the default auto gain), on-screen level audio meters and lower audio noise. On the picture side, you gain zebra stripes (live clipping warning), and crop screen for various motion picture formats.
This sounds promising. More hacks please!
Imaging Professional 