Despite have two large monitors on the desk, I often want even more display. So, I added an old TV as the third monitor. Mounting was very straightforward with the Vitek VT-LCD/PMT pole mount, $55 with shipping. It bolted onto one of the front vertical pipes of the desk, and attached to the VESA screw holes on the back of the monitor. It's rated for a 15kg monitor, which is more than the main 30" monitors on the desk, but I wouldn't necessarily trust the tension of the adjusting bolts to hold anything much heavier than the 15" TV it's got now.
So now I have a third monitor which is useful for baseball or for showing my current task list and Toggl time tracking. I'm still tweaking the details of all the peripherals, which are mostly fine but very frustrating in the tiny details. Currently there are two computers, one Kubuntu and one Windows (after a few years of VMWare, I'm much happier without it). The keyboard is on a KVM switch between the two; the switch is pretty reliable but Windows takes about five seconds to accept the keyboard each time, compared with one or two for linux. Each computer has a dedicated mouse. They both share the same speakers (since I only have one set of ears, and having the sound switched meant I couldn't type on computer A while listening to computer B). The big monitor on the right is always Linux; the big monitor on the left switches between Linux and Windows, and the new third monitor is always Windows. The two big monitors are on their own power bar so I can turn them completely off; the TV has regular power since, unlike the big monitors, it doesn't turn itself back on when power is restored. This also lets me turn off the big monitors while still watching the little one. However, I couldn't get sound to work on the little one because of its buggy HDMI implementation, in which, as far as I can tell, it won't take sound over the HDMI cable but also won't play sound from other sources while the HDMI cable is plugged in.
And the mouse—let me tell you about mouse problems. I had a Logitech and a Microsoft, but the Microsoft mouse kept freezing and glitching. I wasn't sure if that was mouse interference or just Windows, but I switched to a different model of Logitech mouse for Windows and now they both work fine. Also, the old Microsoft mouse didn't have much range when the receiver was plugged into the back of the Windows computer, so I plugged it into one of the monitors and extended that to the computer (which means remember which monitor is plugged into which computer), but it still didn't reach back to the coach. And when I turned off the monitors to watch the little monitor, that killed the mouse. Which actually isn't a real problem since, if I'm going to step away from the computer but leave baseball playing, I will put the baseball on the big monitor so I can see it from across the room. But still.
These are the things I have been fussing with rather than world peace, but on the other hand many other people have tried to cause world peace and we don't have world peace but I have three monitors and the Tigers have the best record in baseball.