Not only is the San Fernando Valley the setting for all sorts of water-related skulduggery and the epicenter of the adult-film industry, it's the home of the San Fernando Illegal Soap Box Federation! There'll be thrills, spills, and possibly arrests galore when those gravitational hoons hit the hills. – Murilee Martin

The San Fernando Valley Illegal Soap Box Federation [sfvisb.com]

Related:
Thrills! Spills! The Greater Los Angeles Soap Box Derby [internal]