Stubbed my big toe a week ago. It bruised and today the nail fell off. Anything special I should do?

Not Much. That must have been one heck of a stub. But no matter, clean it up and you're good to go. Be aware that, most of the time, the new nail will be as normal as the old nail. Occasionally, if the nail root was damaged by the "stub", the new nail may show some degree of distortion. The new nail may appear thicker, thinner, split or even wavy. These changes may be only temporary, but could be permanent.