This sort of thing is largely why we moved homes. The kids needed their own spaces to do as they like. We have a rule now that if you want to do something without anyone bugging you, you need to do it in your own room. (People can share small spaces and still get alone time and space, as I well know, from living in 600 square feet with 4 people for 5 years, but... there are limits to it.) So first off, to ward off this happening in the future, DD would be directed to do such work in her room, and DS isn't allowed in her room without her permission. Also, DD would be free to say that she doesn't want to play with him for a day or a week or however long she doesn't want to play with him, depending on how big a deal what she was working on was.
For the immediate term, DS would have a time out, away from his sister and from me both. He'd have to stay in his room until he could control his temper. He can rant and rave and throw stuff around in his own room as he likes, but it will have to be picked back up and put right when it's clean up time the next morning, and he can't mess with anyone else's property in the process. If DS is wandering around looking for a playmate, I'm already occupied with something or he wouldn't be bugging DD, frankly. If I'm doing a work project while both kids are home and awake, it has to be crucial. If I'm making dinner or doing something else, I'm not available to play. So I wouldn't do any of the "clearly DS needs more attention at that moment, so play with him" solutions, because sometimes one of the kids may really want, or even need something, but it is just not possible at that moment and they have to wait. I don't think "wait until after I make dinner" is unreasonable for a 6 year old, even though they may not like it.
Oh, and I think this also does teach what I'd like them to learn, which is, you are responsible for your own actions. If you're angry, find a way to vent them that does not affect other people adversely. If they go into their rooms alone when they're angry until they've calmed down, I don't see this as a bad strategy.
One of the reasons I am not unconditional parenting oriented is that frankly, I don't have time for it. I think DH might like to do it, as he's very much that way with parenting, and I don't mind if he does more negotiating and more talking about it, but I just don't have time for the endless talking on and on over and over and over. The radical unschoolers I know tend, honestly, to do 1/4 or less of the extra curricular activities we do, and/or they have 1 kid. I work, homeschool, and do twenty-million activities that the kids have chosen and love doing. Personally, I think all those activities we do are more important than learning social skills through exploration as in unconditional parenting style versus learning them through direct instruction as in my more authoritarian style, but YMMV.
Edited by LitMom - 12/7/12 at 12:33am