Is there any way to hook my growing collection of consoles to one TV without having to plug/unplug to switch between different consoles?

I have 2600, NES, Colecovision, and (newly bought) Sega Genesis. There is a good chance I will be getting a couple other systems as well.

Sorry if this is a FAQ, but I just spent 45 minutes searching the forums and couldn't find anything...

Thanks!