The minmus shuttle mission/challenge is where you need to build a space shuttle capable of landing on minmus and returning. I've already done this, so I'm going to challenge you guys to it as well.
CairoJack, If you're Reading this, This is proven to be possible. Hard mode: Go to laythe using a shuttle. Scott manley mode: Go to eeloo using a space shuttle. This shuttle has to be strapped on the side of a rocket and at least 15 tonnes. all the parts must be stock and with a middle booster separating th the SRB's