There is a great deal of curriculum planning material freely available on the Internet. In general, the material posted by education related sources is less elaborate (some might say more achievable). Material offered as part of a broader, subject related site is often quite detailed and ambitious.
It is hard to distinguish between sites that offer off-the-shelf lesson plans, and those that provide lists of links to recommended subject resources from which an educator could construct a unique lesson. Many sites simply mix both types of resources.