How to remove stains from carpets - a pocket guide.

Red wine - White wine.
White wine - Red wine.
Rose wine - More Rose wine. Strange but true.
Tea - Coffee
Coffee - Cocoa
Cocoa - Tippex
Blood - Ring the police, and ask what they use. Be careful of arousing suspicion, however.
Books - These can simply be picked up.
Magma - Leave to dry, then chip off with chisel.
Unicorn Urine - This is largely academic. Since you ask, though: vinegar.