Despite the title, this isn't a museum, but rather a research facility that's closed to the public. With that said, the location within the Valley Life Sciences Building is fronted by an accessible atrium area that includes some cool fossil exhibits, including a Tyrannosaurus rex skeleton. The Life Sciences building is generally open to the public from 9am to 10pm, but may be closed during holidays, weekends and parts of summer.
UC Museum of Paleontology
Berkeley