Spectroscopy? There's an app for that.

When I was in high school, cell phone pretty much only played "snake." I got a phone when I
started driving (I had a fairly unreliable car) and used it to call my parents and John. No pictures, few games, not really any ringtones. I lost it on the band trip. Etc. Pretty common cell phone history. Also common was the inevitable law do not use your phone in class. It cannot be visible. If it rings or vibrates it gets taken away.
Well fine, like anyone would/could call me in class. Like there were any cool games on my phone anyway. My calculator on the other hand was awesome. Mario, Wolfenstein, a few various card games my friends wrote. I even wrote a simple textbase adventure game. Then Joseph wrote a music making program and we couldn't play with our calculators in class anymore.

Back to cell phones.
Someone has realized the ubiquitous and usefulness of these now highly advanced gadgets, Alexander Scheeline made a cameraphone spectrometer. It's available here.

Just another way to let people know how accessible science is.

I know there are apps for everything. There's even a great debate about allowing students to use cellphone apps for...well... everything. However, when I look around the nurses' station at work and see all the docs and nurses looking things up, checking drug interactions, and researching unusual conditions I think, why don't we allow students to do this? Professionals do it. I think we should be training people how to use apps and google to the best ability. Those are real life skill sets we should be training people in.
We don't have to have the periodic table memorized anymore. It can go anywhere.