Pretty enjoyable story you've written here, but I do have just a bit of constructive criticism for you.
Early on, Harry reasons that Hermione should have expressed an interest in Ron. Well, she DID ask him to Slughorn's party, blushing all the while. Ron didn't snog Lavender until Ginny teased him about his never having kissed a girl.
The other thing was just that the ending felt rushed. I think you could have fleshed the Department of Mysteries scene out a bit better. That, and the "Princess Bride" line seemed out of place.
Hope you continue writing!
Author's response
Hi Ivan, Actually, I'm glad for any constructive criticisms I can get. Lord knows I'm probably my own worst criic at times! :D It seems I can stare at a story for weeks, and it's only 10 minutes after posting I spot a typo or an error. For instance, Harry muses about having to vanquish Voldemort before he's even heard the prophecy.. (I've changed it to Voldemort constantly trying to; "it wasn't like he could expect a long and happy life when Voldemort kept trying to kill him." in the version I posted to my group)
You're right about Hermione having invited Ron, but he didn't reply to her, and she didn't pursue the matter with him. As for Ron snogging Lav, as you said, that started almost straight after Ginny rounded on him after Ron (& Harry) caught her and Dean snogging IIRC.
I agree about the ending feeling a bit rushed. That's really due to my intending to write more of the story, but then realising I'd probably written all I needed to as far as the original plot was concerned.
I did wonder whether to include Inigo's line, as I completely agree with you about it seeming a little out of place. In the end I went with it as I had already gone with making the story a parody by including so many of the tvtropes cliches, including; lampshading, virgin superpowers, phlebotinum, etc.
Anyway, if yourself or someone else would like to collaborate on a revised/extended version I'd be interested.