IT ALWAYS GOES OUT AS YOU'RE ABOUT TO BEAT THE HARDEST PART!!! I know this feeling! The first time I beat an Emperor Bulblax in Pikmin 2 (I stunk at that game as a kid, I ended up killing over 2000 by the end of the game) the power went out before I escaped the dungeon and saved. I was screaming.
As a side note, we lost power for two weeks once. I had to put my 3 main handhelds (GBA SP, PSP and 3DS) to the test. It was saddening each time one died, but the power came back as soon as the PSP was about to go (which is surprising considering it's always dead before I'm about to play it).
I had to go out and sit with my chickens a lot though...