Since the future, as it generally seems to be depicted these days, is mostly gloom and doomsday, the new comedy by Eric Overmyer at Center Stage, "On the Verge or The Geography of Learning," deserves points simply for being so upbeat about tomorrow and the day after.

Actually, the play merits points on a number of fronts. But it's the optimism of Overmyer's characters, and their indomitable curiosity about what lies ahead, that give the evening its special flavor. The time is 1888 and three intrepid lady explorers, no less good and proper Victorians for that, are setting out, machetes and parasols in hand, to discover the wonders of Terra Incognita. At first, their adventures hew more or less to form. In the jungle, they encounter fabulous foliage, insufferable heat and wild beasts that pop up, as if in a children's picture book.

Then, around teatime, they spot the dirigible and the cannibal who's dressed like a German World War I aviator. Puzzling, yes, but no more puzzling than the unexplainable notions that have begun dancing, unbidden, in their heads: the copyright date for a novel called "Herzog," a people named the Red Chinese, Burma Shave signs, and Mrs. Butterworth, a celebrity of apparent but indeterminate renown. Forging on to a frosty landscape, they are escorted over an ice bridge by a troll, who once studied at the Actors Studio and rides a "chopper." Their curiosity is further inflamed when they stumble upon a provocative artifact: a small round button inscribed with the cryptic words "I Like Ike." Meanwhile, Fanny (Brenda Wehle), the most conservative of the three ladies, has begun to experience "a burning desire for Cool Whip."

About the moment the truth of this strange expedition dawns on them, it will also occur to you. These explorers are trekking forward through space and time. As Mary (Mary Layne) observes with perfect sprightliness, the future is penetrating their minds "like mustard gas -- whatever that is." What's delightful is that they're absolutely thrilled by the prospect. As they come up on the year 1955 and a Las Vegas-style casino, Alexandra will even borrow from Miranda in "The Tempest," "Ah, brave new world that has such creatures in it."

These ladies are no dolts, however. Their past expeditions have schooled them in realism and they're not so foolish as to expect a peril-free paradise on the horizon. But they figure, quite forthrightly and with no excess of self-modesty, that they can handle whatever comes their way -- Hula-Hoops or holocaust.

Overmyer has a lively literary wit, a mad sense of logic and an eagerness, bordering on the surrealistic, to liberate the stage from its naturalistic shackles. "On the Verge" is the stage equivalent of one of Joseph Cornell's magic boxes, stuffed with bits and pieces of fanciful objects. In fact, it may well be too stuffed for its own good. Overmyer's imagination often overpowers the forward thrust of his play with a myriad of nutty details and you find yourself wondering where, among so many trees, the forest is.

There's another shortcoming: Although the three explorers are engaging examples of no-nonsense womanhood, hiking up their skirts and wading into the stream of time, they do tend to be more alike than they are not. True, Alexandra (Marek Johnson) has a yen to be a lyricist (she will take to rock 'n' roll with a vengeance, when she finally gets to it). Fanny has wisps of nostalgia for the husband she left back in Terre Haute, while Mary's defense of trousers for women suggests her incipient feminism. But despite splendid performances by the Center Stage actresses, you will still look upon these women as a collective. (The single man in the cast, James McDonnell, deftly plays all the supporting roles, ranging from a shaggy abominable snowman to a dapper Palm Beach dandy called Mr. Coffee.)

The production, directed with an appropriate sense of playfulness by Jackson Phippin, benefits immeasurably from the sets by Tony Straiges, who performed similar miracles for "Sunday in the Park With George" on Broadway. Straiges has distilled the curious locales in the script into a series of striking images -- part pop art, part Dada, part once-upon-a-time fairy tale. But where Overmyer's work is sometimes cluttered, Straiges' manages to be clean and crisp. Looking at "On the Verge" is at least as much fun as listening to it, sometimes more.

Eventually, enchanted by such amazements as the surfboard, the barbecue ("the suburban charred meat festival") and the Jacuzzi, Fanny and Alexandra decide to settle down in the year 1955. Mary, still atingle with adventure, resolves to push on. Her mind can't stop "osmosing" all the discoveries that lie in wait -- revolving credit, nondairy creamers, software,, mood elevators, patty melts and meltdowns. Whatever they are!

A mixed blessing, you might say, but her eyes are ablaze with anticipation. As she ticks off the upcoming wonders, her companions can't help emitting little oohs and ahhs of appreciation. In their stalwart hearts, they know that Mary will take the future in her stride. And if Mary can, we find ourselves thinking at the end of this unconventionally chipper play, so, after all, can we.

ON THE VERGE OR THE GEOGRAPHY OF LEARNING. By Eric Overmyer. Directed by Jackson Phippin. Sets, Tony Straiges; costumes, Del W. Risberg; lighting, James F. Ingalls; composer, Paul Sullivan. With Brenda Wehle, Mary Layne, Marek Johnson, James McDonnell. At Center Stage through Feb. 10.