Spend a late night gazing upon the stars from a mountaintop telescope. Typically, you need to rent out the entire Mount Wilson Observatory for over a thousand dollars a night. But the observatory occasionally offers individual stargazing tickets for a chance to look through its 60-inch telescope as well as the 100-inch, which was the largest in the world from 1917 to 1949. Events are seasonal—it's on a mountaintop, after all—and often sell out quickly. Just keep in mind that you'll need to drive up along narrow, windy mountain roads with a 5,700-foot elevation change—and all in the dark on the way home.