You could have downloaded MacDim 2.2 for Mac from our application library for free. This free software for Mac OS X was originally developed by Ibrium HB. MacDim for Mac is included in Theming Tools.
From the developer:
MacDim is a little, but beautiful screensaver for Mac that takes almost no memory. With MacDim screens that haven't been used for a while can be dimmed, monitors that support power saving can also be turned off. To dim up the screen(s), just move the mouse or press a key. MacDim doesn't do any annoying sounds when undimming from powersaving mode.
You may want to check out more software for Mac, such as Occurrence Selector, which might be related to MacDim.