Most glitches, serious ones at least, will ruin a game. This one, encountered during a site's playthrough of Assassin's Creed: Brotherhood, is the opposite of ruined.
Throwing the player into the sky, where for the first time in the series' history, they've actually gotten a good look at an entire city, is so glorious it should have been part of Brotherhood's marketing. Getting so high in, say, Grand Theft Auto isn't that big a deal. There are helicopters in that game.
But a title set during the Renaissance, when you're restricted to the height of the tallest building? It's liberating. It also shows how much of a technical achievement the cities in Assassin's Creed are that they can scale so well despite their immense size.
Assassin's Creed: Brotherhood Flying Glitch [Elder Geek]