When I am at work, I usually lay my iPhone on the desk, on top of a stack of papers. Getting messages used to be problematic, because with my headphones in, and me jamming to the best tunes on the planet, I would not hear the phone vibrate. iOS 5 has a cool little feature that will blink the flashlight whenever you get a new text message. Here is how to do it.
Open the Settings Application -> General -> Accessibility -> LED Flash for Alerts -> On
That is it, your iPhone will now blink using the flash when you receive a text message, and receive a phone call. You can customize which applications turn on the blinker using Notification Center.