This was all years ago... just recently came back to the game.
The first time I managed to rendezvous and dock two parts of a modular space station together blew my mind.
But probably my PROUDEST moment would be the rescue mission after I stranded a kerbal in orbit around the Mun - it was early in the tech tree, and the craft didn't have a docking port, so I had no way to refuel it.
So I concocted a second ship with a four-prong array of scaffold blocks mounted at the front, which flew out to the Mun, made rendezvous with the stranded craft, carefully butted the scaffold scoop up against it at the correct angle, and slowly engaged the main thruster, to shunt it into a return trajectory that would just skim the Kerbin atmosphere. The mission was a resounding success, and all crew returned unscathed!
