I know I'm preaching to the choir here, but if you ever need to convince someone that shooting in RAW mode is a good idea, look no further than here. This is a photo of Trent Reznor of Nine Inch Nails.
Here's the export directly from Lightroom with no adjustments:
And here it is with some MAJOR adjustments to exposure, brightness, and contrast:
There was tons of smoke on stage and banks of huge strobe lights that kept going off. It made exposure and metering an incredibly moving target. The strobes went off just as got this shot. When I got it into Lightroom, it looked completely over-exposed. It was lousy and I tagged it as a reject. I had 1200 photos to go through, so I could only spend a few seconds to rate or reject.
But for some reason I went back to the rejects... and pushed the exposure WAY down. A usable image started to appear... some pushing around some sliders later and I had something that was pretty cool. I'm glad I didn't toss it.
This was a really important lesson... ALWAYS SHOOT RAW and DON'T THROW AWAY PHOTOS. I knew that, but this has given me a great example to convince others. I would NEVER have been able to pull that out of the images if I hadn't shot them in RAW... just not enough bits to do the job in jpeg.
In fact, I'm kind of kicking myself because I didn't even really follow my own rule during the show. I did delete some photos in the camera because I was afraid of running out of card space (brought 3x 4G cards... filled them all). I wonder if I saw an all white screen more than once and deleted it. I wonder what great photos I blew away because of it.