SuperSecret

"Moar Boosters" taken to the extreme. This is by far the biggest craft I ever built, with this beast I accomplished (for the second time actually, but first in 1.0.4) one of the most difficult missions: landing at and returning from Eve, one launch, no refueling, all stock. (just with the aid of Kerbal Engineer Redux and Kerbal Alarm Clock) The craft weighs 3674 tons, with 554 parts, when launched it slows down the game to 2 FPS (mid-range PC). The lifter lifts a total of over 650 tons to LKO. The lander weighs 165 tons with the heat shields, 151 tons without (landed at Eve) The pics are below. Here is the .craft file. Here a video (basically screenshots made every 1/2 seconds, it was too much for a gif) that illustrates the mission.

I was planning to place a refueling station at Minmus, so I sent a probe to scan the surface for Ore. I built the probe, sent it to Minmus (with ion drives, so slow burns), placed it in polar orbit, and when I tried to activate the scanner, I realized I forgot the antenna to send back the data...

No, I started with the full version.

I didn't reuse the remaining of the Tylo lander because it didn't have enough fuel to get back to the main ship after getting into orbit, and getting the ship to the lander was not convenient. The lander was controlled by a probe while docking/undocking.

Here's my entry. It dates back to April 2014 (it was done in 0.23.5). The only mod used was Kerbal Engineer Redux (only while building it). It was done in a single launch, and landed one Kerbal on every moon.

I have been playing KSP since 0.19, and since then I managed to land and return a Kerbal from every landable body, including Eve and Tylo (without mods, apart from Kerbal Engineer Redux) I can post the ships and some screens if you wish.