If you’ve got a digital SLR (Canon, Nikon or Pentax at the moment), Prof. Ken Kobré has developed a cool gadget (Professor Kobré’s Light Scoop, web site here) which vastly improves the on-camera flash by bouncing the light off of the ceiling. Here are a couple of recent examples.
This review is why I bought it and it costs only $30. When you need an indoor flash and don’t want to buy or haul around a big external flash, it does the trick.
And when I reported a strange result, I got a call from Kobré himself (he’s a journalism professor at SF State) to talk about my camera and how to fix it. Great customer service!