I want to subvert a local choir.

I've recently started singing with a bunch of old psychonauts. They're a motley crew already inclined toward not doing as they are told, but due to the nature of choral music they are resigned to mostly singing a load of religious tunage.

What I want are suggestions for anarchisty songs that can be sung in a four part harmony that I can get the music for.

Any suggestions and responses much appreciated.