Next time you pat yourself on the back for having finished The Legend of Zelda: Ocarina of Time, take a moment to remember Runnerguy2489, who finished the entire game 100% — while blindfolded.
Not only did he completely finish the game — collected every item, fulfilled every quest, played every mini-game — he did it without looking. The entire endeavor took a little over 103 hours. Of course, it took him a long time to get familiar enough with the game that he could pull off something like this, though we have no way of knowing exactly how much time he spent preparing.
Blindfolded playthroughs are becoming increasingly popular, but this might be the most impressive one yet.