Long Valley Caldera, sits the remains of an older caldera blasted into the flank of Sierras: The Minarets Caldera, a place of towering spires surrounding a jumbled volcanic void. That's so going on my list of places to hike.
Related to that, it appears that energy from the collision between North America and the Pacific Plate is ever-so-slowly transferring from the San Andreas fault to a deepening trough and system of spreading faults just to the east of the the Sierra Nevadas in the Great Basin. At some point in the distant future, the San Andreas may become an inactive fault, and the Pacific plate will drag all of California to the northwest along a new plate fault, much as it has done with Baja Peninsula since slowly rifting it off mainland Mexico, starting 15 million years ago. See the fourth page of this geology digest article for illustrations.
California being transported to the Pacific Northwest may not necessarily be awesome, but it's certainly a rather epic scenario.
For those who are curious, it sounds like 80% of the present day collision energy is expressed in movements along the San Andreas fault, while the other 20% finds an outlet in the deformation of the Western Great Basin's Walker Trough, which roughly parallels the Sierras.