Let’s begin with this: It would be a hell of a lot of fun.

Rex Ryan running it back with the Jets, manning the big office he once occupied for six years at Florham Park, making bombastic guarantees he won’t make good on, refusing to kiss rings, taunting opposing players, making jokes about his affinity for women’s feet, taking his players out to “get a damn snack.’’

For the Jets, who are mired in a perpetual state of losing and listlessness and haven’t been to the playoffs since Ryan was their head coach (2010), a return of Rex would provide instant energy.

Rex back in the big chair would brighten the white-H๏τ spotlight on the Jets. And, as we’ve come to know, attention is as intoxicating for Jets owner Woody Johnson as ayahuasca is for Aaron Rodgers.