You reminded me of some topics I used to create many years ago for the community to post up their best records in certain games. I thought I did this at Cubed3, but looks like it was a different forum I used to go to.
I used to post up my records for games like Sonic Advance and F-Zero, and other users would post their best times to give us a list of the best times across the site, to show who was best at which level.
I've always been a fan of sharing and competing in time-based games, as seen with my Star Fox Adventures Test of Strength topic I made here, to see if anyone could beat my times in that.
I think time trial-based topics for any game would be great. We could definitely have time trial topics for MK8, and Smash Bros has many timer events and challenges, like fastest time in particular modes, or best scores in Home Run Contest etc. We could collate the top scores from people here very well. Just a pic should be enough proof, and vids if people can do it.
Tournaments for MK8 are possibly a bit tricker to sort because we have casual fun ones now and then that probably don't function well for competitive play. I don't know how a tourney for MK8 could be organised in a competitive way, but ideas definitely welcome.
Leaderboards do seem to be the much safer, easier and more fun thing we could do, for not just MK8, but a wide range of games.