Very pretty ending - black loses his queen to a fork or is mated. I very much doubt it was tactically wise for black to expose his fianchettoed king-side position earlier. Neither was it for white but he was in a better position to exploit the hole. Good positional play by white to restrict the bishop to a8.
I'm not sure if this counts as a sacrificial ending, but I went the exchange down for enough pawns (as it turned out) coming out of the middle game to find a win Game 1424401.
Moves 42 - 46 are instructive; I realised (after stopping it) that my opponent wanted to do something that was clearly in my interests, so I repeated, and my opponent did what by then both of us wanted him to do. The lesson is that if your opponent is trying to complete a manouvre the best defence may sometimes be to allow it - the corrolary is that if your opponent allows you to do something you really do need to check that it is they and not you who've missed something...
btw it's nice to see a thread about endgames for a change.
Originally posted by Freddie2006 Why can't the king just move somewhere else; like h8?
Black's overriding problem is that he's copious numbers of pawns down. 2R's vs a Queen is roughly worth a pawn to black, but that really doesn't make up for the rest of them. Since white seems to have initiative and can protect his king (the knight on the 8th file may as well be off the board...) black will eventually lose.