This is an extremely easy example of chords for the song "Worlds Collide" made for The 
Nazi Zombie mode of Call of Duty: Black Ops. The riff can be taken from the song "Lullaby 
for a dead man" however these are only the chords for the song. * means Palm-Muted

"Worlds Collide" by Two Down
Intro: Am,C,D,F x4

Am*                                                       C*
Verse 1: Well I've been here before...and I've sat on the floor in a grey,
                  D* Am (x02210@1)        grey room...  And I stay here all day...and I don't sleep I just
                   G (320003@1)             DAm
         play in a grey, grey room... Until the end of my days...I'll feel
                                  C (x32010@1)            D (xx0232@1)        nothing but pain in this grey, grey room...

Am (x02210@1)   C (x32010@1)               D (xx0232@1)        FChorus: (133211@1) Well I've been packing punches all my life,
       Am (x02210@1)   C (x32010@1)          D (xx0232@1)     F (133211@1)        Been dying on the inside (outside),
       Am (x02210@1)  C (x32010@1)           D (xx0232@1)      F (133211@1)        And on this day I promise you,
              Am (x02210@1)     C (x32010@1)       D (xx0232@1)  F (133211@1)        That when our worlds collide,
               Am (x02210@1)  CD F(Am (133211@1)C (x32010@1)D F)x3
         we'll die...
         Am (x02210@1)   CD

AmVerse (x02210@1)2: Well I've been here before...and I've spilt blood on the floor of
             C (x32010@1)            D (xx0232@1)Am (x02210@1)        the grey, grey room...  And I stay here all day...and I feel nothing
                   G (320003@1)                     D (xx0232@1)        but shame in this grey, grey room...

Am (x02210@1)   C (x32010@1)               D (xx0232@1)        FChorus: (133211@1) Well I've been packing punches all my life,
       Am (x02210@1)   C (x32010@1)          D (xx0232@1)     F (133211@1)        Been dying on the inside (outside),
       Am (x02210@1)  C (x32010@1)           D (xx0232@1)      F (133211@1)        And on this day I promise you,
              Am (x02210@1)     C (x32010@1)       D (xx0232@1)  F (133211@1)        That when our worlds collide,
               Am (x02210@1)  CD F (133211@1)AmC 
DF
         we'll die...

Am (x02210@1)                                  AmC 
FD
Pre-Chorus:  And on this day I'll promise you...
           Am (x02210@1)                                  AmC 
FD
             And on this day I'll promise you...
           Am (x02210@1)            And on this day I'll promise you...
           Am*
              Well I've been here before, and I've sat on the floor in a
           C (x32010@1)             D (xx0232@1)          grey, grey room (help me).

Am (x02210@1)   C (x32010@1)               D (xx0232@1)        FChorus: (133211@1) Well I've been packing punches all my life,
       Am (x02210@1)   C (x32010@1)          D (xx0232@1)     F (133211@1)        Been dying on the inside (outside),
       Am (x02210@1)  C (x32010@1)           D (xx0232@1)      F (133211@1)        And on this day I promise you,
              Am (x02210@1)     C (x32010@1)       D (xx0232@1)  F (133211@1)        That when our worlds collide,
               Am (x02210@1)  CD F(Am (133211@1)C (x32010@1)D F)x2
         we'll die...
         (A Dsus2D E)x2

And that's it (i's a bit flawed but hey, it's still pretty good).Visit the Two Down 
website at http://www.twodownmusic.com/