A very unexpected event of things is the S59 second round matchup of Buffalo Stampede vs Atlanta Inferno. 
At first sight you may think why that? #2 vs #12, 3-0 so far and everything according as you think. Wrong. The big favorite on the series was Atlanta Inferno, they started at home into the series with winning the tough Atlantic Division. They came out on top from their very, very close division, and showed the nerves of steel they have. After a first round bye, it was the debut in the playoffs now for them.
On the other hand we have Buffalo, they already had to play in the first round. They also played in a very competitive division, but only came out second of that. Also starting the series away is an indicator that the favorite is the other team. 
This series shows, that the current playoff structure and system is one that provides surprises. Even an underdog like Buffalo can outplay the big favorite Atlanta and bring them to the verge (for now) of losing the series, even getting sweeped is possible. We'll see if Atlanta can bounce back or Buffalo completes the full surprise, a special one, one for the history books.