How to play Crazy by Gnarls Barkley
This song was massively popular when it came out back in 2006 and I love to get this one out for students. It's great for beginner students as it has two repeating chord progressions with the addition of a great sounding Esus4 to E move.
The strumming pattern here is an 8th note Down Down Up Down Down (1 2+3 4 ) that matches the rhythm of the single bass note picking played by the guitar in the original song (which you can have a listen to below).
The song sheet can be downloaded by clicking on the image below.