Your phone can reveal, and record, a lot about the place in which you live. As part of my PHD project I am undertaking to record many different perspectives on a particular location but only by using my phone. So I have had fun finding and making all sorts of apps and gadgets which you can attach or download into your phone in order to find different kinds of information.
Some of you (particularly the teachers who read this regularly) may be interested in the stuff I found so am putting out this post for you....
Sound: Of course you can record sound on your phone, but if you really want to take it up a notch and record high quality sound you need to find ways to augment the internal microphone of your device. If you have an Andriod phone it is a tricky process to be honest. The external microphones that have been made specifically for smartphones are usually Apple specific devices. a Samsung devices (and some Nokia), have a jack that (mostly) takes devices built for Apple but often the accompanying app isn't available for Android. I have ordered a Tascam Microphone for my iPad, and have some different cables and adapters for my Samsung Note to see if I can connect an external microphone. Will keep you posted and put up some sounds to show the difference in quality. There are also other kinds of microphones: contact microphones record vibrations of different kinds, and hydrophones record underwater. If you want to see some really creative work done with contact microphones take a look at Bruno Zamborlin's work. You might also check out the power of recording 'place' at these sites: Wild Sanctuary and NatureSounds (although from my enquiries most of these recordings were done with professional equipment like digital records and directional microphones - not mobiles.
Visuals: If you want to take microscopic pictures you can try Keeploop. which has an actual lens rather than relying on digital enhancement as many of the downloaded apps. There are few of these being developed, mainly with medical use in mind. Some really interesting work is going on in Africa to assist local health workers to test blood for Malaria using a device developed by a team from Cellscope at Berkeley.You can get all sorts of add-on lens for your phone right up to a rig that makes it look like an actual SLR camera - check out TurtleJacket.
Easy Macro does a little lens that is quite cheap and worth looking at if you just want to do Macro shots and don't want to be limited to your phone camera's range. Other companies do telephoto, wide, macro lens combos.
If you are interested in Timelapse there are several different apps (Android or otherwise) that will help you do the job, and to ensure you have a steady camera take a look at another great Kickstarter originating product called the Slingshot, which is atripod adapter/universal grip for your phone (Joby do a similar product called GorrillaPod).
If you want to take underwater shots then maybe think about iOtte. They do a kind of skin for your phone that scares the bejebbers out of me with my expensive phone, but others may be game to try. Otherwise something like Aquapac's much bulkier version would work but maybe not give as good a picture quality (lots of outfits do these waterproof bag/pouch versions).
Other dimensional activities - of course for those of you who are interested in finding other kinds of information about a site, Mr Ghost might be just your thing. It records EMF readings (Electro Magnetic Frequencies at a location so, apparently, it can tell you if you are being secretly fried by your microwave, interfered with by your hair tongs or spied on by spirits. My name is down for one (again through Kickstarter) so will let you know the results when I have tested, along with a number of the products above.
Jpeg corruption programme made by developer, Charlie Kindel. The photos on this post are made using the process. So if you want to hack into a the code of a photo and can't be bothered using long work-flows in Gimp or Paint.Net then this might be a quick way to do the work.