I have an aversion to hills, especially when riding a bike. This is not ideal, because I live in San Francisco and some days it feels like an entire city of hills. This bike ride is one of my favorites not only because it goes right through the heart of Golden Gate Park and ends up at Ocean Beach on the Pacific Coast, but there are—you guessed it—no hills.
Rent a bike at Golden Gate Bike Rentals on Haight Street and cruise through the park to the sea. On the way back, it's a little tougher because you are headed on a gentle upward slope, but you can always catch the number 5 bus and put your bike on the rack for the return journey.