Playing Damia against a Dragonlord Silumgar theft deck (and a Mathas, Fiend Seeker deck). I cast Diluvian Primordial, play a Knowledge Exploitation from Silumgar's graveyard against himself.

I look through his library, find and play Bribery, again against himself. I find a Chancellor of the Spires, use it to play Bribery again, this time finding his Sepulchral Primordial. With the Primordial, I reanimate his Deadeye Navigator (emphasis important, I refuse to put it in my decks) and pair it with Chancellor of the Spires.

I flicker Chancellor, play Bribery again, finding his Gray Merchant of Asphodel, which gets paired with Deadeye. From there on, I spam Merchant triggers for the win.

A good reason to play Knowledge Exploitation yourself.

Playing a four-way free-for-all. I'm piloting Ephara, God of the Polis, the guy across the table runs Ezuri, Claw of Progress. PhyZuri is usually a pain, but luckily, I'm playing WU control, and my Brago, King Eternal and Lavinia of the Tenth are doing a swell job of keeping him at bay. Then he finally disrupts my board and plays some merfolk that makes his creatures with counters on them unblockable. His army was still detained, however, so he had to pass the turn.

On my turn, I just nonchalantly tap four mana and show him my Reins of Power. He panics. Takes him a full minute of freaking out before he realizes he can do things like take all counters off his Spike Feeder. We swap, and of course, since his creatures are unblockable, what he gets from me doesn't matter. Even with all his damage control efforts, his own pumped-up army is still too much and it one-shots him.

And that's why you never play your unblockability until the last minute =)