Bell's palsy is a fairly common condition that causes the sudden paralysis of half of the face.  Effected people can't fully close the effected eye and have an asymmetric smile, since only one side of the mouth moves well.  The cause is unknown and has always assumed to be viral.  The symptoms slowly resolve over a few months. The accepted treatment has always been steroids and acyclovir (an anti-viral medication), each for about 10 days.  More