A user on Reddit discovered a cool trick if you are using an iPhone on iOS 7. If your flashlight is turned on and the phone is asleep, you can wake the phone, and tap the camera icon on the lockscreen to turn the flashlight off.
Here is a video demonstrating this feature, courtesy of iPhoneHacksTV:
The Reddit user also noticed a less useful but cool trick. On the lock screen if you hold onto the camera slide up shortcut, drag it halfway up, then slam it back down it will bounce.
You can bounce it so hard that it goes back up and unlocks the camera. Cool attention to detail by Apple.