Bones Brigade is great.  As much as a documentary can have a direct sequel, BB is a sequel to Dogtown and Z Boys, which is an all time favorite for me.  If you haven't seen DTaZB yet, I can't recommend that one any higher. 

Another sort of side story to that one is RISING SON, the story of Christian Hosoi.  He was a legendary big air skater in the late 80's early 90's, and pretty much the direct rival to Tony Hawk.  He also innovated his own move, the Christ Air.  He was doing great, until drugs and the collapse of vert skating in the mid 90's basically forced him into rock bottom.  It gets a bit preachy towards the end, but he's a fascinating dude to be sure.

I saw Cleanflix a few months ago, the doc about the Utah company which would edit R rated movies for you. An interesting subject, and I kind of agree with the idea:I grew up watching Blues Brothers, MASH, and other stuff edited for TV, but can't, yet, show the same movies to my niece because there are no edited versions. Even if the original director created one (Landis shot non-nude scenes for Animal House, for example, for the TV edit, and Reitman filmed alternate takes for Ghostbusters to get rid of the swearing)

The documentary, though... not good. It relies heavily on interviews with a couple guys, then levels a horrible charge at one of them which has nothing to due with the subject. Either find another talking head to replace him, or don't bring that thing up. You're left with some basic information, and that's about it.

Let's play a game.  Name a doc you like, and I'll quote your post and respond with a recommendation that you might like.