Laughing gas

Is recreational use of N₂O dangerous? An interesting debate in Ben Goldacre's Bad Science blog. Ben's article on the MHRA sinking their credibility by talking obvious rubbish is good value as always, but the comments underneath address the more general question of recreational N₂O and safety. See comments 8, 9, 14, 17 (mine), 18, 19, 21 (mine), and 23 in particular.