ADPI American Dental Partners, Inc. (MM)

•    Share prices of dental services provider American Dental Partners, Inc. (NASDAQ:ADPI) rocketed up 79% to close at $18.58 after the company announced that it has agreed to be bought by JLL Partners Inc for $19 a share

•    Amgen, Inc.’s  (NASDAQ:AMGN) share prices increased 5.91% after the biotech company announced its decision to buy back nearly $5 billion of its own stock

•    Restaurant chain operator Cracker Barrel Old Country Store Inc (NASDAQ:CBRL) raised its guidance for the year 2011. Following this development, shares of the company gained 6.10% to close at $45.55

•    Riding high on the recent success of its film "Puss in Boots," ranked as the top movie in American and Canadian theaters for the second consecutive week, shares of animation company DreamWorks Animation (NASDAQ:DWA) advanced 11.96% to close the day at $19.47

•    General Dynamics Corporation.  (NYSE:GD) announced that it will acquire reinforced military vehicles makers, Force Protection, Inc. (NASDAQ:FRPT) in a deal worth $360 million

•    Shares of network-technology provider TEKELEC (NASDAQ:TKLC) increased 14.04% after the company agreed to sell itself to Siris Capital in a deal worth around $780 million

•    RBC Capital upgraded shares of CVS Caremark (NYSE:CVS)  to "Outperform" rating from "Sector Perform" rating

•    Wells Fargo upgraded shares of Eagle Rock Energy (NASDAQ:EROC) to "Outperform" rating from "Market Perform" rating