A goal of mine for some time has been to land an asteroid pusher on a rock, mine the rock for ore, convert that ore to fuel, and use that fuel to push the rock into orbit around Kerbin. I finally managed that goal this last weekend!
I spent about half an in game year checking for rocks that didn't have insanely angled or distant approaches to Kerbin, and finally one came by that had a ~12 degree angled approach at about 6M km.
So I sent my tug to rendezvous, and after a few adjustments it was on it's way! But le gasp! It was nearly out of fuel! Oh man, this was going to be super rough! The closest encounter was about 8km off, and with the last gasps of fuel I carefully twerked the intercept, crossed my fingers, and upped the Time Dilation.
Nervously watching the asteroid approach, I extended the Klaw and dropped time to normal... 1km. 500m. 250m. 100m. 50m... 10m... KAPOW, contact! I had to spin a little bit to snag the rock, but I hit it!
Extending the drills I started gathering ore, and converting it to fuel, and thought man, this is awesome, I'm totally doing it! Then I toggled to the map, and immediately swore - I was 12 minutes to the asteroids orbital periapsis.
Turning on the fuel converters Lf+Ox, Lf, and Ox settings, I juggled maximized fuel generation against power loss for 12m and ended up with about 1/8th of a tank. I toggled the drills, retracted the Klaw and repositioned to the asteroids CoM, and started my retrograde burn.
Juuuuuuuuuust as the asteroid entered a stable if somewhat eccentric orbit, I zeroed on fuel. Not too bad! By the time I got to the ascending node I had full fuel tanks and started my circularizing and altitude reduction burns.
Now I've got the first asteroid in a circular ~350km orbit, and will start constructing my asteroid base.
... with gigantic melancholies and gigantic mirth, to tread the jeweled thrones of the Earth under his sandalled feet.