So frustrated you could scream? Tom and Ruth Roy have a suggestion: Go right ahead and bellow. Today, in fact, you might have some company. This is, after all, International Moment of Frustration Scream Day, when all the exasperated folks in the world are invited to let off steam by going outdoors at 1200 Greenwich time and screaming their heads off for 30 seconds.

"We will all feel better, or Earth will go off its orbit," say the Roys, a couple from Lebanon, Pa., who dreamed up the holiday about four years ago. They've concocted a total of 36 such observances over the years in the interest of getting everybody to lighten up a little and enjoy life.

"It's guilt-free fun," says Ruth Roy, 42, an herbalist, freelance writer and former radio talk show host, who refers to herself and her husband as "metaphysical gardeners." It all started about eight years ago, when Tom Roy -- then the morning guy on radio station WIOV in Lancaster -- was told to spice up his broadcasts. He discovered Chase's Annual Events, a two-inch-thick compendium of proclamations, anniversaries, festivals and other calendar-cloggers.

Noting that Chase's accepts new entries, Roy promptly filled out a form and invented his first official holiday -- Northern Hemisphere Hoodie-Hoo Day (Feb. 20) -- during which citizens are encouraged to yell "Hoodie-Hoo" at high noon in an effort to hasten the arrival of spring. "The reaction was great," says Roy, 49, now a professional actor. "We were off and running."

Next came Panic Day (March 9), which gives people license to "run around all day in a panic, telling others you can't handle it anymore." Nov. 30 is Stay Home Because You're Well Day, which gave birth to the Wellness Permission League, the Roys' two-person umbrella organization. A sampling of other noteworthy dates in the Calendar According to Tom and Ruth Roy: Feb. 13 is Get a Different Name Day; Nov. 19 is Have a Bad Day Day ("For those who are filled with revulsion at being told endlessly to have a nice day"); Sept. 11 is No News Is Good News Day ("Don't read, listen to or watch the news today and you'll feel better tonight"); April 26 is Hug an Australian Day; Aug. 8 is Sneak Some Zucchini Onto Your Neighbor's Porch Night and March 26 is Make Up Your Own Holiday Day.

It's anybody's guess how many people actually celebrate the Roys' holidays. But judging by the mail they receive -- more than 1,000 letters a year, including many from people interested in joining the Wellness Permission League -- it's unlikely that any of their observances go completely unobserved. Celebrants usually find out about them through radio shows, computer chatlines, Chase's or similar publications.

The holidays, according to the Roys, are especially popular among camp counselors, social directors, chiropractors and others hungry for fresh ways to keep a captive audience engaged. On June 2, for example, Larry Hosack, activities director at a nursing home in Kennebunk, Maine, organized a spirited celebration of Yell "Fudge" at the Cobras in North America Day.

This Roy creation is aimed at keeping poisonous snakes far, far from our shores. "Fudge makes cobras gag," explain the Roys, "and the mere mention of it makes them skedaddle." Says Hosack: "It worked. There weren't any cobras to be found. The residents loved it."