Go on youtube and search for Kerbal. You will find plenty of examples.
The BFE-5000 mod. The thing's designed to go with 3 metre wide parts from other mods... the stock parts are only 1 metre wide and the engine itself is about 15 metres at base. It is practically impossible to use all that 22000 thrust power at maximum thrust (stock parts typically only go up to 1500 (as of 0.18). yes, the BFE-5000 has 15 times the thrust power of stock parts!) without running out of fuel very quickly, or, more commonly, destroying EVERYTHING ABOVE THE ENGINE. Note: it is so wide at the base, that it will invariably bump into the launch tower, which will result in flipping the rocket over. So even if you manage to get it to leave the ground without exploding into a zillion bits due to the unbridled power of the engine itself, the resulting collision will eventuall explode it anyway. But if you get it to work, a single-stage-to-orbit rocket is quite feasible. And... really silly looking. The name is possibly a DoomShout Out. Update: The removal of the launch tower in the current version of the game means that there's nothing for the nozzle to bump up against... so BFE to your heart's content...!
Angering the Space Kraken BIG TIME just by making a few Gigantor Solar Panels break off of his spaceship.
That came off easily. Too easily... *Kraken mode engaged, followed by the Awesome Face song* WHAT IN THE CRAP! *Pauses game, notices glitchy Kerbal* What the hell is this!? *Pauses again* *Again* THE POWER *You know the drill* OF KRAKEN *Once again...* COMPELS YOU!
Managing to BREAK PHYSICS ON KERBIN. As in, the objects-floating-around-not-colliding-with-other-stuff breaking physics. The kicker? He did so just by making a Fragmentation Rocket.
That's actually because version 0.20 fixed the Lithobreaker glitch, but still!
Absurd Contraptions: Making a drop pod that can only slow down using winglets, and making a cannon that uses lander cans to get back to Kerbin. The kicker? They work perfectly. And we're talking about a guy who loves to make odd contraptions to torture Kerbals.
His 50k subs special consists of him making a SACRIFICING RITUAL by strapping 50 Kerbals to a weird machine and sending them to Jool via Hyper edit, each Kerbal representing 1k subs. Funnily enough, Jool doesn't end up destroying the universe. He then retries on the Mun and activating Dynamic Warp. The result? A spaghettistorm of Kerbals going everywhere as the rocket explodes, distorting to horrifying degrees. This guy doesn't use the Kraken; HE IS THE KRAKEN.
Arriving on the Mun with the most basic parts to do some science and thus unlock more parts with his research... only to realize he forgot to research solar panels and thus can't send the data back home due to a lack of energy.
Jury-rigging water vehicles using nothing but intakes. Yes, not even engines, just intakes.