Top 10 most Tweeted moments ever

As at 24th November 2011
(Rank - Event - Tweets per Second - Date)
"10 - Osama Bin Laden’s Death - 5,106 - 1st May 2011
9 - East Coast Earthquake - 5,449 - 23rd August 2011
8 - Japanese Earthquake and Tsunami - 5,530 - 14th March 2011
7 - Last Game of the 2011 NBA Finals - 5,531 - 12th June 2011
6 - UEFA Champions League (Final) - 6,303 - 28th May 2011
5 - 2011 BET Awards - 6,436 - 26th June 2011
4 - New Year’s Day, Japan - 6,939 - 1st January 2011
3 - Brazil Eliminated From Copa América - 7,166 - 17th July 2011
2 - FIFA Women’s World Cup - 7,196 - 17th July 2011
1 - Beyoncé Reveals Baby Bump - 8,868 - 28th August 2011"
Source:  BusinessInsider, 22nd November 2011