"Honey, I found a way I can install lights without cutting into our drywall!"  Two broken water pipes, two emergency runs to the hardware store for repair pieces, who knows how many pounds of damaged water-logged drywall and insulation, a night and morning with no water, 11 (hands-on) hours later and we're looking at 13 (and counting) holes in our ceiling.  A far cry from the prediction of zero holes (other than the light cut-outs).  I asked him if he knows how to repair drywall.  His reply "No, but I will soon enough, and I'm going to get really good at it".  

Home-improvements gone horribly wrong.