Now, for the boomers who refuse to grow up, is a pop-up activity book to help ease the misery of that ultimate grown-up subject: menopause.

“MenOpop” provides women — and the men in their lives trying to understand what they’re going through — a humorous tour through this middle-age rite of passage guided by the cranky Menopause Fairy (who used to be the Tooth Fairy before “the change”).

The book and Web site, www.menopop.com were developed by 50-something Kathy Kelly and the 30-something partners — Peter D. Straus, Kenwyn Dapo and Michelle Cohen — whom she was driving crazy. They work together in Fill’er Up Productions Inc., a multimedia entertainment company in Manhattan.

Kelly, like the estimated 4,000 women a day entering menopause, was experiencing many of the typical symptoms — hot flashes, mood swings, insomnia and temporary memory loss — that emerge when a woman’s ovaries stop producing the hormone estrogen.

The book offers plenty of fun features: a 3-D uterus with “going out of business” signs; a Dial-A-Mood wheel; and a chance to play the MenOland game with six game pieces and a spin wheel, (Insomnia. Spin again — you’re the only one up; Forget Fido’s name. Make name tag, skip a turn.)

It retails for $24.95 and can be ordered off the Web site or by calling 1-888-MenOpop.

The book’s warning: Hang on to your sanity — it’s going to be a bumpy ride.