I'm surprised that no one has created a comprehensive mod collection that focuses on The Beatles. I can just imagine regular infected being screaming beatlemania afflicted fans clamouring towards players skinned as the fab four. Yoko Ono could be the witch (with her music and vocals used). Each map could be based on The Beatles and their various albums and performances. I can see maps for "Back In The USSR" and their famous rooftop performance in london. Costumes would change by the era.