with your multitouch pad you can open and close your stack with two finger gester . Just Up your two finger and stack is open down your two finger stack will be closed same rule apply on mac os x dock icon when we bring the cursor on any dock icon and up our two finger in multitouch pad the expose is working even if the application is not open it will show recent open files.
So you might have an iPhone 4. You might have the facetime app for OS X. Wouldn’t it be neat if your mac could auto-answer calls??
Picture this, your mac is at home/office, you are out and about, you facetime your mac and have an instance surveillance system!
open “terminal” and type:
defaults write com.apple.FaceTime AutoAcceptInvitesFrom -array-add +61410003111
(where the number at the end is your own cell number, inc area code)
You can also allow it to answer from other apple-ID’s instead of cell num’s, AND auto-answer everything..
We all know or may have forgotten how at least to do a screen grab of a particular part of the screen with shift+cmd+4 but, try adding a space to the end of that 
Check it out, shift+cmd+4+space = camera icon. Now click on a window or even the dock, tool bar or your icon set on the desktop. Try it now…
Pretty cool huh!
I received an attachment via E-mail and wanted to print it straight away.
1. So, I saved the document.
2. Selected it in Finder (not opened it) in Space 2
3. Then used the “File > Print” in Finder
4. The document was opened and printed
5. My word processor closed automatically again
In the meanwhile I was working on a document in a different Space.
from Klara:
Alt+Cmd+D hides the dock and pressing the same brings it back.
I tested this in Leopard (10.5.8) but it should work with Snow Leopard (10.6.x). Please comment telling me if it does work in 10.6.x.
In Terminal, type the following
defaults write com.apple.dock mouse-over-hilte-stack -boolean YES;killall Dock;killall Terminal
Terminal will close, and your Dock will flash. Open a stack, and you now have a gradient when you mouse over an icon.
I know it’s old. Just thought I would post it here. Also, to reverse it, copy and paste the same code, but replace YES with NO.
* from mrsir2009
(ALL VERSIONS OF MAC OSX) Open Script Editor which can be found by typing “Script Editor” into spotlight. This works for any version of OSX, even the BETA I think but no one uses that anymore, so full of glitches, features you take for granted just aren’t there… Anyway, when you go into script editor type in: say “Hello, how are you doing today?” Copy and paste that, you can replace the text inside the speech marks with anything you want the computer to say, then click the green play button.
I’m new here so I’m not sure if you have this tip or not but it is quite funny to listen to the computer say things that you type…
There’ll be plenty more of these, but here’re 2 I’ve spotted:
Smart emptying of the trash:
How many items are there in your print queue? Now you know with a little badge:
