Armadillidiidae is a family of woodlice, a terrestrial crustacean group in the order Isopoda. Unlike members of other woodlouse families, members of this family can roll into a ball, an ability they share with the outwardly similar but unrelated pill millipedes and other animals. It is this ability which gives woodlice in this family their common name of pill bugs or roly polies. The best known species in the family is Armadillidium vulgare, the common pill bug. --wikipedia
Any moist area outdoors.
My son collected these earlier this afternoon with his friend. Eventually they released them back into their habitats when I revealed we couldn't keep them as permanent pets.