Visage also lets you customize the text of a number of system alerts. You can add your name or favorite phrase, which is a lot of fun if combined with Leopard's text-to-speech function: Have your Mac read alerts to you when they're displayed.

Add more effects to iChat and PhotoBooth
Leopard introduced the ability to show special effects and custom backgrounds in an iChat video chat, with the same effects available in Photo Booth. Both applications make use of Mac OS X's Quartz imaging layer and a series of Quartz compositions to apply the effects to input from a Mac's iSight camera.

More iChat Effects is a package of four-dozen additional Quartz compositions designed for iChat (though they also work well with Photo Booth), all of which make chatting and picture-taking fun and crazy. Ever wonder what you'd look like in a funhouse mirror, with a neon outline or dripping fire? Try it, and you'll know.

Also check out the QuartzFX.com site for more cool Quartz compositions -- or try your hand at building some of your own with Apple's Quartz Composer.

Create a Recent Apps Stack
Our final Leopard tweak brings us back to customizing the Dock (and requires limited use of the command line).

This easy trick places any recently launched applications -- the same ones listed in the Recent Items option from the Apple menu -- conveniently in the Dock, making a great launcher tool for apps you use frequently.

To add this Stack, launch the Terminal (located in the Applications/Utilities) and copy and paste (or type) the following, then hit the Return key:

defaults write com.apple.dock persistent-others -array-add '{ "tile-data" = { "list-type" = 1; }; "tile-type" = "recents-tile"; }'

Then restart the Dock process by typing the following and hitting Return:

killall Dock

You can remove the Stack by dragging it out of the Dock as you would any other Dock item.

Want more?

Can't get enough Leopard tweaks? If you're comfortable using the command line, there are a number of additional subtle changes you can make to the Dock, Finder, and other Leopard components. Check out Part 1 and Part 2 of the UsingMac.com series on command-line tweaks for Leopard.

Ryan Faas is a frequent Computerworld contributor specializing in Mac and multiplatform network issues. You can find more information about him at RyanFaas.com. Computerworld is an InfoWorld affiliate.