Outdoor workouts work well in some areas, especially when 10 minutes away from us, we have one called the 'Calabasas Stairs'. It is a simple 1/2 mile hiking trail to the stairs, in which you then go up 374 stairs to the top, and back down again (or back up if you want). This was actually pretty cool to do, in the early morning.
It is right off the 101 Freeway here in Calabasas, California