Rimmer: Are you smoking, Lister - in the drive room? Lister: Yeah, I stopped for quite a while but I'm back on them now. I love this one. It still makes me laugh out loud after watching it many times. Most of my favourite RD gags tend to be those that manage to smoothly (and often quite subtly) reference a certain sci-fi element of the plot without compromising the sitcom element. And I think this is a basic yet brilliant example of that.