House Centipedes Scutigera coleoptrata are one of those creatures that send all the primitive synapses in our brains jangling on full red alert, but actually they are more or less harmless and earn their keep in the house by eating undesirables such as cockroaches and silverfish. They are very much more visible in the cooler months, when they tend to be active inside the house. In the summer they often move outside.
For some really professional pictures of house centipedes and a properly knowledgeable blog post on them, go to Piotr Naskrecki's Smaller Majority. You will be amazed and fascinated.