This past week I picked up a cheap Mac Mini, 2006 edition. I wanted one for my iTunes and basic stuff (I'm still a PC guy at heart). It was in good shape, but pretty much stock. It has a 1.6Ghz Core Duo processor, 1 GB ram, but only a 60 GB HD. We have a few a work, but my experience opening one a few years ago wasn't so good. However, I found a great site and decided to press on with a full on upgrade - 2 GB RAM, 500 GB HD, and replacement of the processor up to a 2.33Ghz Core 2 Duo, so I could go up to Lion. After watching the videos a few times, I popped that sucker open, swapped parts (tons of dust bunnies inside, btw - gave it a good cleaning), put it back together, and rebooted. No issues! I even flashed the firmware to 2,1 afterwards so it will now accept 4 GB RAM instead of the max 2 GB that the 1,1 takes (that'll come in handy when I do put on Lion).
So almost 3 weeks into the Summer of Chuff, what all have you started/completed, my brothers?