Flashlight:
This one is fairly obvious, but there is more than one way to light up your iPhone. There are several flashlight apps you can download, but an equally effective, DIY method is to switch you camera mode to "video," then turn on the flash. Et voilà! Let there be light.
Lamp:
Here's one that lets you utilize crafty physics to your benefit. You can make a lamp out of your iPhone by placing a clear, filled water bottle over the LED light. The liquid will magnify the light's effect. Use it in a pinch (or during a power outage).
Alerts:
Go to Settings > General > Accessibility > Hearing. Select "LED flash" for Alerts. Now, every time you get any kind of text, email, phone, or social media notification, your phone will flash. Just use it discriminately, or people might start to hate you.
Strobe light:
Download RoboStrobe, which allows you to further customize your LED's utility and speed. Lumos! You have a makeshift strobe; you can even incorporate the water trick mentioned above to really get the light party pumping.
Musical strobe:
RoboStrobe can also flash in time to music! Just stream a song on an external device, and let the lights pulse to the rhythm. Great for bedroom raves.
Morse code:
It's hard to stay elusive in the world of 24/7 digital communication and NSA monitoring, but you can always resort to a classic: Morse Code. With Light Morse Code, you can instantly convert your text into light flashes. There's also TeleTweet for photophobes, which converts your message into proper Morse code — dots, dashes, and all.
Projector:
Just like your grade school teacher of yesteryear, you too, can now project images on a wall — without spending money on fancy equipment (well, minus said iPhone). Use its LED light against transparency film, and you should get a makeshift projected image on your wall. You can take it even further and use a shoebox and magnifying glass to make the images or text even bigger. Or, you can just have fun with shadow play. [Mashable]