So in Beautiful Katamari there is a 40 achievement for playing the game for 50 hours of playtime and an 80 point achievement for 100 hours. Let's just be straight: there is no way in hell anybody would ever actually reach 20 hours (let alone 50 or 100) in that game naturally. 
 
Yeah, so I've just been leaving my 360 on all day and while I sleep and stuff. I already got the 50 point achievement and saved after I got it. Then, if I did the math right in my head, I was at somewhere like 99 hours and 45 minutes-ish, but then the power in my entire neighborhood just goes out for no reason. So I lost all of that...greeeeat. 
 
There's been some other instances where that happened to me. Like there was that extremely hard mini-game level in the first Super Mario Galaxy where you have to hurl bombs at the trash and right when I got the Star the power went out.