I made a monitor stand
I made a monitor stand out of black gas pipe and fittings, compression tees, and an adapter bracket.
The compression tees (as in pipe fittings, not clothing) were an awesome find. They have rubber gaskets inside that made a surprisingly tight connection once the end caps are screwed down.
The galvanized metal fitting is a bracket made for using metal pipes for things like mounting rails and chin-up bars. The holes are 38mm apart, as opposed to 100mm on the standard VESA mount, so I made an adapter bracket. I made the adapter out of 6mm birch on the laser cutter at Metrix Create:Space though it would be easy enough to make at home -- but lasering's just so easy! I even countersunk screw holes using the laser.
I'm really impressed with the stability of the stand. I had been worried I'd need to add clamps under the compression tees to make sure they wouldn't slip, but it turns out they're far more solid than expected.
If I ever go completely insane and decide I need more monitors, I'm thinking I could make an X-Y setup, with two vertical bars, on which horizontal bars could be mounted. Each row could still have its height adjusted, plus this would allow an up/down tilt on each monitor.
Total cost for this was about $70, $8 of which was for the (very optional) laser cutting.