#3: The Mirror of Erised
Harry’s luck starts early in his academic career, and third place goes to the events at the end of his first year at Hogwarts. Dumbledore places an enchantment on the Mirror of Erised to protect the Sorcerer’s (or Philosopher’s, for the Brits) stone inside. The enchantment ensures that only someone who wants the stone but doesn’t want to use it can get it out of the mirror. That Dumbledore, so smart! Thus, when Voldemort reaches the mirror, he can’t actually get the stone from it. Now remember, this is still in-recovery, book-one Voldemort, so chances are good that Dumbledore’s plan is gonna work.
That is until Harry "The Chosen One" Potter shows up. Noble to a fault, he certainly fits the bill as someone who wants the stone but does not want to use it. Luckily for him, despite putting the stone in extreme danger by getting it out of the mirror, everything works out. Luckier still is that Dumbledore—for reasons unknown—decides to reward Harry’s recklessness, and gives Gryffindor additional points so that they overtake Slytherin and win the House cup. Go figure.