The 2012 Summer Olympics kick off tonight in London, and no one seems more excited than the Olympic athletes themselves!“Talk about a blast from the past … First Olympics way back when … The start of my last one Tom!!!,” Michael Phelps tweeted, along with a photo of memorabilia from his debut at the 2000 Olympic Games in Sydney.“Doing whatever it takes. #goldorbust,” soccer star Abby Wambach tweeted on Thursday morning after the U.S. women’s soccer team defeated France in its Olympic opener.“I remember after Beijing feeling like an eternity to get to the next games,” track and field sprinter Allyson Felix tweeted. “So crazy that it's finally time. Opening Ceremonies tomorrow!”“Pre-meet rituals in progress. Giving myself a mani/pedi, shave, dinner, then rest … 4x100FR tomorrow. Relaxed yet excited! #London2012,” 11-time Olympic swimming medalist Natalie Coughlin tweeted.“Just beginning transformation of nails … ” says beach volleyball player Misty May-Treanor, who tweeted a photo of her nails – painted in honor of her quest for gold.“Headed to Opening Ceremonies for London 2012 w/ @MrsBClay & @FactoryAgency11, can't wait,” tweeted decathlete Bryan Clay while on his way to Olympic Park in East London.“OLYMPICS!!!!!!!!!” tweeted legendary tennis player Serena Williams, who is participating in the Olympics for the third time.