Oh, Flo Rida's 'Right Round' "samples" another song of the same title by Dead Or Alive - many artists have remade that song, so I don't think Flo Rida actually ripped it off.
Kelly Clarkson "Already Gone" ripped off Beyonce's "Halo".
Though, it wasn't Kelly's fault. The same guy (Ryan Tedder of One Republic) wrote the two songs. And it could have been the other way around, because apparently, Ryan worked with Kelly first and THEN Beyonce.
New Kelly Clarkson Song Admittedly “Ripped Off” from a Beyonce Hit | Music Vixen Blog