Ok, today, I had two big ideas.
Speaking with Gabriel, I came up with a mini device; pluggable to the computer via USB, a PAN or whatever. The device would be a medical device that you attach to your finger. It would take various metrics; including temperature, pressure, pulse and, if necessary, it would pinch your finger and read the most basic chemistry in your blood (glucose, acidity, etc).
The device should be as low cost as possible. This device would enable a doctor, via <a href="https://helpouts.google.com/">Google Helpouts</a>, to read the metrics in real time and let you know if you're seriously ill or not.
This device would enable anybody in the world with an internet connection to consult a doctor.
The other idea is a more artistic one. There should be a web app or web service where, a lazy musician, could upload his/her songs and, by gathering a lot of information from the song (frequency, tempo, key, lyrics, etc), the app would generate a video, with closed caption.
The video wouldn't be random. The info gathered from the song, would give the app enough info for it to gather Creative Commons pictures and video; rendering an re-editable video (by you, obviously), in tempo with the song and with images that have something to do with the lyrics, the sound and the mood of the song. Maybe, even identify a basic style (blues, rock, jazz, etc).
Those are two good ideas if I may say so myself ;)