No one will accuse the creators of "Tripping the Rift" (10:30 tonight, Sci Fi) of being fainthearted. In the opening episode of this new computer-animated series, Chode (Stephen Root, "Newsradio"), the bulbous, Barney-colored commander of the Jupiter 42 space vessel, and his much more refined robot Gus (Maurice La- Marche, current voice of Yosemite Sam and other Looney Tunes characters) sign up for a time-travel excursion that promises to take them back to the beginning, the Big Bang, where they hope to see God. Instead, they accidentally run him down. When they return to their own time, the universe is...