Alright, so I searched for this within the forum, but couldn't find anything that answered my question, so I hope it hasn't been asked before.

What do we know about the Ravenclaw common room? I don't actually remember ever reading about it in the books, but then, I haven't re-read the series as recently as I'd like.

One thing I read frequently is that it doesn't have a password, but rather, the portrait gives each student a riddle and lets him or her in if the answer is reasonable. Is this a canon fact or just something lots of fans have adopted? It does seem very Ravenclaw-esque, though on the other hand, it's not like only Ravenclaws can solve riddles, so it wouldn't do too much for security.

Any other tidbits or general impressions that are known? How it's set up, furnished, etc., the general atmosphere of the place?

And if little is actually known about it, what are some of the most common generalizations/assumptions/accepted facts about it?

I just hatched a plot bunny for a short story about a Ravenclaw student in which the common room plays a significant role, so any input/advice would really be appreciated.