Who wants cake? Two of music's biggest stars are celebrating a birthday today: miss Avril Lavigne is 28, and Lil Wayne turns the big 3-0! So, what better way to celebrate than with a Lyric Battle of epic proportions? In this corner, we've got Avril's hit song "Smile", which is exactly what she'll be doing on her big day. And in the other corner, Lil Wayne's "My Birthday" is appropriately-titled for his special day! But who has the better lyrics? You decide...