Like the title says. Thanks to a couple of power strips and an AV component selector, I have my PS3, PS2, and Wii fully hooked up at the same time. My Dreamcast's power cord is hooked in, but my AV selector only lets me hook up three different cables. But I have enough outlets that I can have up to five consoles plugged in.
And in case you're wondering what an AV selector is:
Only mine lets me hook up three component cables and has a knob that lets me switch between them.
And in case you're wondering what an AV selector is:

Only mine lets me hook up three component cables and has a knob that lets me switch between them.