Basically, Ronnie's house of cards tumbled last night. People (finally) began comparing notes, which led to the confrontation of the year. So much happened that I highly suggest just going to Real and watch it all unfold.
Edit: Ok, I've gone back and watched lots of footage from different cams. The entire fight actually starts about 11:15 or so, right after Laura left the HOH. Chima, Natalie, Ronnie, Lydia, and Kevin began arguing about how Russell should have been the replacement nominee. Natalie and Chima, in particular, get into it.
Lydia then goes off and complains to Russell how Natalie acts like she's in charge. Russell smartly plays into it. A few minutes later, Russell pulls Ronnie into the storage room and advises him to settle down and not act so paranoid. This conversation gets heated, as Russell calls him on talking behind his (and everybody else's) back.
Russell then calls everybody into the bathroom and states the obvious - "if you want to know what is going on, why wouldn't you call me up there and ask me what is going on, rather than planting seeds of doubt. You should ask me what is going on? Does that make sense? DOES THAT MAKE SENSE?" Ronnie complains that Russell shouldn't talk down to him (hehe).
A few minutes later, almost everybody is in the backyard, and Laura wants Russell and Ronnie to come out to tell everybody what she has said or not said. Russell and Jordan jump in, but Ronnie refuses to answer to them as the conversation is expanded to all of Ronnie's shenanigans.
Ronnie retreats to the HOH with Chima, who points out that what he's saying should be said to the entire group. They're all yelling for Ronnie to come back out, and finally he screams "you're the one going home" to Laura before slamming the sliding glass door.
They're ALL now talking shit about Ronnie, except for Lydia and Jessie. Ronnie attempts to chat with Russell, who calls everybody into the house to listen to Ronnie claim he hasn't lied to anybody. An exhausted and defeated Ronnie retires to his room, as the rest of the crew continue to make fun of him for the next couple of hours. Yeah, they're a bit full of themselves, and I don't necessarily believe that every single one of them would put him up if they win HOH on Thursday.