How to dim everything but active window?

Somewhere, in the past, I remember reading that you could dim out everything except the currently active window, but I haven't been able to find anything on it since then. Is this a built-in feature of OS X or only possible with a 3rd party app? Any info on how I can do this?
Thanks.

On my iMac G5 set up Stock it's the F10 key. Is yours a Notebook or imac?

however you can not use the application when in this mode.

Mine is a macbook pro....
F10 adjusts the keyboard backlight brightness, F11 is Expose 'show desktop' and F12 is Dashboard.

There's not another option in the Expose preferences, but maybe somewhere else? I'm running OS X Tiger 10.4.8.

I remember reading about a program that dims the background and lets you focus on just one application. I tried it out and works exactly like it's advertised. Best part is that it's free :black:

Think

Check System Preferences and click Desktop & Expose. See what Keys do what. Here is a screenshot of mine.

You guys aren't reading his post. He isn't asking for Expose, he's asking for something that will let him focus on just one application while dimming everything else. Expose, while it dims the desktop, doesn't let you access any particular program by itself. So directing him to System Preferences is just going to waste his time.

Since Mac OS X doesn't have the particular function that he's asking for built in, a third part app is required.

Thanks, Kash. The "Think" app does the trick.

You guys aren't reading his post.He isn't asking for Expose, he's asking for something that will let him focus on just one application while dimming everything else.

Click to expand...

Ahem:

Somewhere, in the past, I remember reading that you could dim out everything except the currently active window, but I haven't been able to find anything on it since then.

Click to expand...

http://www.freemacware.com/doodim/ =)

theres also a free app off apple's download page called OmniDazzle which lets u do that and more..its pretty sweet....(my favorite is the footprints that follow ur mouse across the screen)

Well it seems I somehow forgot to ever reply to you guys. So sorry about that....

I ended up using Think and it works like a charm. I haven't tried any of the other recommendations because so far, Think does everything I need. Thanks for the suggestions!