Thanks to butwhatifitisnt for the following.
In Season 5, Episode 15, "The Variable" in the scene where Daniel is crying over the news report of the plane wreckage, his hair totally changes from when he's watching TV to when he's talking to Widmore, see link :) (I"m sure this is because the first part was filmed in a previous season, so they didn't redo that part of the scene...just thought it was funny)
Before
http://www.flickr.com/photos/jlyn74/3671829905/
After
http://www.flickr.com/photos/jlyn74/3672638300/