Spaces is considered "cult" comedy with rather out-of-the-ordinary jokes and a
lot of references to other cult / scifi films and events (to prove my point, I point out that there's a separate set of subtitles on the DVDs specifically to point out what film references certain scenes include... expect Pulp Fiction, Star Wars, Robot Wars and goodness knows what else).
For further information visit the "official" fan page:
http://www.spaced-out.org.uk/It's packed with info about the series as well as some stuff about Shaun Of The Dead.
On that note...
****ING AMAZING. OH MY GOD. If you see one film this year, make it Shaun Of The Dead. I don't care if you don't usually like cult humor - it doesn't matter now. This film makes it accessable even to Reebok Wearing Estate Monkeys™. Watching it on the first day of release I witnessed something I'd never seen before - an entire cinema laughing more than once through a film. Everyone (and I mean everyone from people like me to married couples to little children and goths (not mutually exclusive)) was laughing throughout.
Go. Watch. Cherish.