Marc Summers Is Still Up for a Double Dare. (Hold the Green Slime.)

Rehearsing at a studio space in Times Square earlier this month, Marc Summers was crouched low, engaged in a conversation with God. Such scenes are staples of one-person shows like the kind that Summers is bringing to Off Broadway, but his arch tone suggested he wasn’t approaching this existential moment too earnestly.

“What is my purpose in life?” Summers called out, wondering what he should do if he encountered disappointments or impediments on his journey.

A booming, recorded voice answered that life may be full of pain and regrets, but it also offers humor and joy. “The only question,” the voice said, “is are you ready for it?”

After further contemplation, Summers answered confidently. “I think I’m ready,” he said, pausing for effect. “I think I’m ready to take the physical challenge!”

Summers is 72 with a head of mostly white and gray hair, but his toothy smile and exuberant cadence still make him easily recognizable to the generation of television viewers who were introduced to him as the host of the children’s game show “Double Dare.”

“Double Dare,” which debuted in 1986 on Nickelodeon, blended a trivia competition with outrageously messy obstacle courses. A team of two youthful contestants could dare a rival duo to field a question, but their opponents, of course, could double dare them back. In that case the original team had to either answer the question or submit to a physical challenge.