If you have a point-and-click digital camera made by Canon, you may be able to turn on all sorts of features usually reserved for more expensive SLRs. That includes live histograms, depth-of-field calculation, under and overexposure highlighting, and -- best of all -- shooting your pictures in RAW. The secret is CHDK, an enhanced, free software replacement firmware.
It is not clear what CHDK developer Andre Gratchev intends the initials CHDK to stand for, but the user community has speculated that it means Canon Hacker's Development Kit. In any event, you don't have to be a hacker to use CHDK; it is as close to a plug-and-play camera enhancement as you will find.