Another idea for my personal effort at patent prevention - the phone translator.
I've been thinking of going to China on vacation. One thing that worries me is I don't speak the language at all. Hopefully a lot of things will be made easy by helpful Chinese people, good guidebooks and gestures, but some things remain scary. Two big problems are road signs and menus.
Now a bunch of technologies have become fairly solid and common in the last few years. These include OCR (optical character recognition), automatic translation, and mobile phones with Java and cameras. A great device would be something you could point at a sign or menu, and it would translate it for you into your language. A mobile phone seems like the ideal device to put this onto, as they often have a programmable computer, a camera, and a screen, and they are natural to take on holiday.
Obvious extensions would be to have something that would do audio translation, especially the other way, so I could type something in in english, and it would translate it and say it in chinese. That's probably too CPU and memory intensive for my mobile phone at the moment, but it should happen eventually.
There's nothing new under the sun! If you are willing to carry a laptop, something pretty good like this exists already: The PenPower Mini ScanEYE (note I haven't tried this but it looks cool). And even on the Wikipedia entry for mobile phones they suggest a translation function, but don't say whether they mean audio or text. They don't mention using the camera.