I know this has probably been done before, but I'm just interested in seeing the results.
Till the World Ends vs Teenage Dream
Hold It Against Me vs Last Friday Night (TGIF)
Inside Out vs California Gurls
I Wanna Go vs Firework
How I Roll vs Peacock
(Drop Dead) Beautiful vs Circle the Drain
Seal It with a Kiss vs The One That Got Away
Big Fat Bass vs E.T.
Trouble for Me vs Who Am I Living For?
Trip to Your Heart vs Pearl
Gasoline vs Hummingbird Heartbeat
Criminal vs Not Like the Movies
Up N' Down vs Part of Me
He About to Lose Me vs Wide Awake
Selfish vs Dressin' Up
Have fun.
Though I use TTYH, IWG, and TTWE