Ok, so I like whats on here already but if you play acoustic guitar like me and love to 
hip hop songs, stick a capo on the 3rd fret and play:

Am / C / Dm / Em
Am / C / Dm / Em (not 100% sure bout that last Em)

Then:

F / Em / Am / Em

Sing along and it works really well. Check out the ace alternative vid to.