There is an 'Easter Egg' in Episode 1 where James is answering his mobile. The wallpaper on his phone is an Andy Warhol style picture of the cast as they appear on the series logo.
The black door behind which Blake the Goth lives, is covered with a flag of Dimmu Borgir, a Norweigan Black Metal band. There are also runes above the door that read "Abandon hope all ye who enter here" - a reference from the classic novel 'Inferno' by Dante.