TV Tube Sleep
Makes your screen turn off like an old TV tube when you press the sleep button. I got a Google Nexus S and noticed it has this cool effect when you turn it off, so I immediately worked on bringing the feature to the iPhone and 3 hours later it was finished. Watch the video of it in action below.
Available to buy in Cydia for $0.99
Versions on other repos is a trial version that displays the effect up to a maximum of 10 times.