For those who use Terminal a lot in Mac OS X, Vincent Danen recommends the Visor program, which allows you to make the Terminal window appear and disappear as needed with a simple keystroke.
When it comes to using the command-line interface on OS X, the de facto standard program is Apple's Terminal.app, found in /Applications/Utilities/. There are other Terminal programs available; most notable is iTerm, a good alternative to Terminal. Prior to OS X 10.4 and 10.5, anyone who was a "power" command-line program user would opt for iTerm because it had much better features. Recent versions of Terminal have corrected most of those deficiencies.
If you are like me, you live in the Terminal. There are tabs open for various ssh sessions, irssi, mutt, and text editors like vim or joe. The main screen of my Mac is essentially one giant terminal. So any hacks or productivity improvements I can use to enhance Terminal usage are always welcome.
With that, I recently came across an application called Visor. What Visor does is use a hack to have the Terminal appear and disappear with a single keystroke (the default is CTRL-'). When activating, the Terminal slides out for use and with the same keystroke is hidden. This is certainly easier than hiding or minimizing the Terminal when it isn't in use. The nice thing with Visor as well is that it is the real Terminal, just with some clever trickery to get it out of the way when you don't need it, and the Terminal is always one keystroke away, saving time with mouse movements and clicking. Visor is free and open source.
To begin, download Visor. Visor is a SIMBL plugin, so SIMBL is required as well (SIMBL is the SIMple Bundle Loader, which enables hacks to work with various programs, such as PithHelmet in Safari). Download the current version SIMBL, which is 0.9.7a for Snow Leopard.
Install SIMBL, then unarchive Visor. You may need to create the ~/Library/Application Support/SIMBL/Plugins directory first, and then move Visor.bundle (which comes from the zip archive Visor is distributed as) into this directory. You can then start Terminal, and Visor will start.
On the OS X menubar will be a new icon for Visor, which you can use to configure it (this opens Terminal's preferences and focuses on the new Visor pane). You can configure how Visor interacts with Spaces and the various animation effects to make it visible. If you click on Settings, you will see the various themes available for Terminal, including a new theme called Visor.
This theme is what will be used for the Visor terminal. If you have a preferred theme, or a customized theme, it is very easy to make Visor use it instead. Simply rename the Visor theme to Visor.org and then duplicate the theme you prefer to use. Rename that duplicated theme to Visor and restart Terminal.
Note that you can still have standard Terminal windows, as well as the Visor window. Visor is now active and calls up the Terminal with a keystroke. Tabs work, and so does everything else (with the exception of Window Groups). Considering that small amount of lost functionality, and the easy window hiding/activation that Visor permits, it's a nice addition if you find yourself wishing for an easy way to get the Terminal out of the way when you don't need it, and having it active quickly when you do.