So, I was reading this Ask Metafilter thread about the morality and logistics of dying a cat different colours for festive occasions, and someone linked to this story about a farm in Alaska that injects dye into eggs, resulting in multi-coloured chicks. That is funny and awesome and SO TEMPTING all at the same time! :)

Advice to heed! "From a practical standpoint, I can suggest one method not to use: do not gather 5 people in a small bathroom, hot-box it, and then watercolour your white cat. Just sayin'. The cat didn't actually seem to mind too much, but we sure got paint on every single surface in there! This was almost 10 years ago, and the cat in question is still alive and well and demanding affection, so clearly no permanent harm was done to her. Also, be aware that if your cat's paws get wet for any reason, you will be the lucky owner of furniture/carpeting with tiny colourful pawprints all over them."

Also: "When we were younger, we spent a lot of time altering our indoor cats' appearances. None of our techniques resulted in any animal's physical suffering, and they remained crazy yet affectionate. Don't use food coloring; the stuff rubs off the second it touches anything damp. The best coloring technique: cherry kool-aid dip. (It helped that our cats liked water.) Rinse well -- and scrub the tub after; that stuff will stain like a mofo -- and you have a pink cat for a couple of months. (I don't recommend grape. It fades to a nasty grey color.)"