Since I recently retired I have all this time now to goof around in the shop. I have a couple of projects in the works but I’ve been adding a three-stage filter regulator to my CNC. When I bought my compressor a few years ago I added a DIY after cooler dryer shortly after and that does a great job but I wanted to ensure that I would have dry air to the CNC since I’ve added a laser.. This is a fantastic CNC and glad to be a part of the this forum..
Alum parts, adding camera, finally installing dust collector, add fans to move air, upgrade table setup…it never ends 
Well, last year I upgraded from Mach4 to the EX Controller and servos. That was huge. And I just finished making a much improved spoilboard. Not exactly a CNC upgrade, but right now I’m working on learning the ins and outs of toolpaths in Fusion - with mixed success so far. I agree that these are fantastic machines and this is a great forum.
Tell me more about that… what are you trying to toolpath in Fusion and where are you running into issues?
I’ve been experimenting with home made vacuum pods for work holding. It works, but not sure it is worth it compared to just bolting something to the spoilboard for most situations.
Also tinkering with moving the tool pockets just slightly off the table so I can put long boards under them.
Or did you mean what useful thing am I actually building with the machine instead of for the machine? 