Amid a pandemic that has closed down fitness centers worldwide, a spate of companies has muscled their way into the booming at-home fitness market. In just the last two weeks, three-year Future, which promises at-home customers access to elite training, closed on $24 million in Series B funding; and Playbook, a nearly five-year-old fitness platform that helps personal trainers stream their content (and charge a monthly fee for it), raised $9.3 million in Series A funding. Now, serial entrepreneur Jason Goldberg — who has founded a number of venture-backed startups — is taking the wraps off another live-streaming platform and marketplace.