What 2002 movie's tagline starts "One man is about to do the unthinkable. No sex. Whatsoever"?

The 2002 movie whose tagline begins “One man is about to do the unthinkable. No sex. Whatsoever” is 40 Days and 40 Nights.

The romantic comedy stars Josh Hartnett as Matt Sullivan, a young man who makes a vow to abstain from sex for the 40 days and 40 nights of Lent. His self-imposed challenge becomes increasingly difficult when he meets Erica, played by Shannyn Sossamon, while friends and coworkers turn the vow into a public spectacle and betting opportunity.

Directed by Michael Lehmann and written by Rob Perez, the film uses the abstinence challenge as the engine for its comedy. The tagline deliberately reduces the premise to a memorable advertising hook: the supposedly impossible decision to give up sex completely for the duration of Lent.

The title is sometimes remembered as Forty Days and Forty Nights, but the film’s official title uses numerals: 40 Days and 40 Nights. It is also distinct from unrelated films and religious references involving the biblical phrase “40 days and 40 nights.”