First foray into watercooling was about a year ago, all went pretty smoothly. Over the next 6 months I changed a few things around, so I became very familiar with the process of draining, refilling and leak testing the loop. Next I decided to upgrade my video card, so went and grabbed a Koolance block and a brand spanking new GXT480 superclocked.
After installing the block, I leak tested for 2 hours and thought it was good to go. Powered the system up, started running F@H and went to have a nap... woke up a couple hours later to a small lake of blue coolant under my case, and a good sized puddle all over the nice new fermi.

The tubing had almost completely come off where the run from the cpu went down to the gpu; I imagine I must have pulled on it trying to wiggle the card into place.
So I've gone back to leak testing over night
PS: I prayed to the computer gods that I would always be faithful to those responsible if my rma was approved for the card... so i always buy from Ncix and my next video card will be another Evga