In Kerbal Space Program i circumnavigated Kerbin in an amphibious vehicle. It was a challenge someone in the forums set and it took me about 20-30 hours of play time in total. I documented the whole thing in the forums but it unfortunately got lost during the transfer to the new forum site :( . It was genuinely the most fun I’ve had in a game since there were so many problems to solve, i even had to make a crane to lift the vehicle up the ice shelf at the pole.
EDIT: looks like the post actually does still exist on the forums! You can see it here if anyone is interested
flying_monkies
WadeTheWizard
okawari