I'm one of those people that needs more than one computer to work. My main workstation is a 15" MacBook Pro that is connected to a 20" Apple Cinema display. To its right is our 20" iMac, which serves as our media server, backup server, and VMware test machine. Due to limited desk space, I didn't want to have multiple keyboards and mice laying around. My first thought was to use a standard KVM switch to switch my keyboard and mouse between my Macs. But that requires a lot of USB cables, and I really didn't want that kind of clutter behind my desk. I needed a clean, elegant solution.
 
Enter Teleport - it's a software-based KVM that works over your home network. You simply load Teleport on each Mac that you want to share your keyboard and mouse and enable sharing. Your "secondary" Macs (the ones without keyboards/mice of their own) will show up as monitors that you can position around your primary Mac's display. Then, when your pointer moves offscreen, it will "hop" over to the next Mac. Teleport even allows you to share information between your Macs. You can drag and drop files, as well as the content in your clipboard.
 
For those of you not running Macs, be sure to take a look at Synergy - an open source alternative that runs on Windows, Linux, and yes, even Macs. One nice thing that Synergy has going for it over Teleport is the ability to mix and match your computers on your LAN. So you can control a Windows machine from your Linux box, etc.