For at the seventh time since November, a port-o-potty was set on fire in San Francisco this morning, according to the fire department. This most recent portable blaze, all of them happening in or near Russian Hill, went up on Taylor Street near Union and Filbert at 12:45 a.m. this morning. No one was injured. SFPD asked to eyewitnesses to report any suspicious porta-potty activity to the police department at 415-553-0123. No matter how funny all this is.