Sadly, unreliable on Lion
I used to use the free Hazeover version before buying its appstore incarnation. Its an app I love to use when I need to focus a little more, unfortunately its become fantastically unreliable on Lion and typically crashes immediately after launch.
Every now and again it holds together but as I cant rely on it I dont really use it much any more and am switching to using full-screen apps when available - I only offer this as a suggestion in case anyone else is having issues with hazeover on Lion.
tayup about HazeOver • Distraction Dimmer™, v1.2