I Gotta Feeling by The Black Eyed Peas is in G at 130 beats per minute and runs 4:43 across 110 bars. It uses 3 chords — G, C, Em. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? I Gotta Feeling guitar melody tab.