Luna Lovegood is a Ravenclaw girl the same age as Ginny Weasley with long, scraggly dirty-blonde hair, and pale, strangely protrubant eyes that make her look permanently surprised. She dresses 'weird', is usually pretty soft-spoken, but isn't afraid to laugh loud and long when amused.
Luna is truly in a world of her own; she often gives off the impression of being completely out of touch with reality, or as the book states, she gives off an aura of 'distinct dottiness'. She has a deeply calm and accepting aire about her... almost wise....and is completely confident in her beliefs, no matter how outlandish they appear to other students. She is often teased and picked on by others who think she's weird: they call her 'Loony Lovegood' behind her back (though she's well aware of it) and steal her things throughout the school year. But it never upsets her. In fact, nothing really seems to upset her, except the time Hermione insulted the magazine her father edits. That magazine is the Quibbler, considered ridiculous by 'sensible' wizards and witches, but it is apparently quite popular nonetheless. The Quibbler helped rally public support for Harry when it published an interview with him about the return of Voldemort, as the Daily Prophet was too biased to print something like that.
Luna joined Dumbledore's Army and was present at the battle at the Ministry of Magic, where she held her own for a very respectable amount of time before being minorly injured by a Deatheater. Even before this point she was becoming more of a friend to Harry & Co., by supporting their Quidditch team (very publically and loudly) and helping them distract Umbridge when Harry needed to use her fireplace. I have a sneaking suspicion she might have a bit of a crush on Ron.... but that remains to be seen.
I think the coolest thing about Luna came at the end of OotP when Harry was struggling with the loss of Sirius. Luna was the first other person Harry knew who could see Thestrals, and when he asked her about it, she manages to comfort him without any of the typical sympathetic responses one usually hears when in mourning. Instead she told him, in that straightforward, unquestioning Luna way that the ones we love aren't really gone... they're just "lurking out of sight", and we'll see them again one day. The way she says that makes me tear up everytime I read it.
I am SO HAPPY that J.K. has introduced a strong, awesome character from Ravenclaw house, and I hope we'll see much more of Luna in the next books. **waves a tiny Ravenclaw flag**