Here's how to play Mad World by Tears for fears, also covered by Gary Jules (who kept my favourite band The Darkness off the Christmas number 1 in the UK...ggrrrr! :)
This song uses just two easy chords for the intro and chorus, E minor and A major, making it fantastic for beginner to play and sing at the same time.
The chords uses the sequence E minor, G major, D major and A major, making appropriate for Level 4 of my online Beginner Course lesson series.
Mad World Guitar Lesson
Mad World - Tears For Fears (original recording)
Mad World - Gary Jules version