The Knockoff Project documents “album cover spoofs, goofs and send-ups.” I was surprised with how many bands outright stole album designs from other groups. Or perhaps they were homages? :-p

Along the same lines, The Covers Project has “[built] a database of cover songs (songs performed by an artist other than the original performer) with the intention of creating cover ‘chains.’” At the time of this post, they’ve listed almost 24,000 songs (!).