Home 9th Annual Marble Falls Soapbox Classic Adult Soapbox Derby Historic Downtown Marble Falls, Texas Father’s Day Weekend June 15-17, 2018 RACING REGISTRATION OPENS APRIL 1st. The DEADLINE is always the last day of May. Do not show up on race day and expect to race if you are not registered. Click HERE for more information. Special Thanks to the Event Sponsors We can’t do it without your support!