Going mobile As you heard here earlier this month, Gregory Pike, the renowned San Francisco street performer who has trained a rat to stand atop a cat standing atop a dog, has departed our fair city following a conviction and fine on a charge of "public obstruction" for drawing large crowds at Union Square. We caught up with Pike this morning in a telephone interview from Lake Tahoe, where his animal companions -- Booger the dog, Kitty the cat, and Mousey the rat -- are apparently charming