Well, not many bites. I guess we could open it up to useful things you've built too?
I have already posted a few of these in the past but I'll go first...
Two burner forge-
Anvil Stand Made with two flanges, 2 3/8 pipe and full of sand (home made welding bench in background)
Hydraulic crimper. I needed to crimp some 0 Ga. Cable ends without removing cables from the truck. I couldn't find a hydraulic crimper for sale in my area so I built this for a hammer style crimper. It worked like a dream.