Millipedes do not actually have a thousand legs, they usually have between 100-400 (2 sets of legs per body segment). With each molt they add more segments and with new legs.
The housing can be any suitable small aquarium or container that can take a 15 cm depth of leaf mould (either beech or oak) substrate, mixed into this should be a quantity of soft dead wood (approximate. 10%). The substrate should be kept damp but not wet; pieces of bark placed on the surface of the leaf mould act as mulch and help prevent the substrate from drying out too quickly. Most species are easy to keep and breed.