Real time receive NOAA APT weather broadcast
Just use your regular radio receiver on the NOAA frequency and let the sound goes to your iDevice (it works with the native microphone when existing or with a special cable -- note that youre responsible of making a cable that wont damage your radio nor your iDevice). Press record, youve got the current weather map!
Please see http://f4hla.free.fr/iPhone/iAPT_Manual.pdf for full details on usage and context.