Elon Musk, the wealthy innovator behind PayPal, SpaceX and Telsa motors, recently blogged about his next idea Hyperloop (detailed pdf). This one, however, he proposed as a thinking man's journey as opposed to putting up the funding and infrastructure himself. Musk asks that for California's massive investment in transportation, it should provide a massive improvement in critical areas:

• Safer
• Faster
• Lower cost
• More convenient
• Immune to weather
• Sustainably self-powering
• Resistant to Earthquakes
• Not disruptive to those along the route

He proposed Hyperloop, a series of elevated tubes through which "trains" would be suspended on air cushions and travel at 600+mph between cities. Theoretically running alongside major highways, the Hyperloop trains could transit San Francisco to Los Angeles in 30 minutes.