We had to ground DS1 (15 at the time) about 9 months ago for a piece of appalling behaviour.
It consisted of no going out - even to sports, no friends round, no computer at all, no mobile phone, no ipod, no TV, We even took his nicest clothes. He also wasn't allowed to go upstairs and sleep on his bed.
He was allowed to read, play in garden, help around the place, and to earn back privileges through good behaviour.
We also talked to him lots, both to try and understand why he'd done what he did, and also to make it clear that we did a lot for him, and currenlty planned to do a lot more - all of which could change if he didn't shape up.
I also told him that if he did it again, I'd take the door off his room, and remove everything of his except basic clothes.
Thank goodness I haven't needed to. It would be far too much work.