The recorder.
"Just pick any one from the song, record it, upload it, and copy and paste the riff list with the one you just did exchanged with another of your choice."
woops didn't see that
EDIT: Dibs seek and destroy
EDIT2: o.k I've recorded Seek and Destroy and done 1:25 which is 4 riffs is this how long you want it? or like 25 seconds long?