OK, so it’s your last weekend on Earth. NASA has broken in on “Survivor” to announce that a stream of asteroids is heading for your house at 47,000 mph.

This is the big one. Even Will Smith can’t help us now. What to do? The Cobb Manor Theory is, when in doubt, have the Best Time Possible and spend the Most Money Possible, whether you have any or not. That theory was employed last weekend for a mammoth anniversary celebration of 18 years of unwedded bliss.

In order to keep Blue Eyed Susan interested for another year, an act of largesse was required. A gift certificate introduced us to the 21-room Danforth Inn, in the heart of downtown Portland, with room rates at $135-$285. That’s a little out of the traditional budget, but if the asteroids are coming and there is no way out, consider this: The Danforth is a sterling example of Federal architecture, a mansion built by shipping merchant and silversmith Joseph Holt Ingraham in 1821 or 1823. Portland residents still smarting from the 1775 sacking and burning of the city said only a fool would build a silversmith shop so close to the harbor. But Ingraham knew that the three most important components of real estate are location, location and location.

Around 1900 it became the Portland School for Girls, a precursor to the Waynflete School. The first remodeling came when it was purchased by Elias Thomas, president of Canal Bank, rich enough to add Ionic columns, Celtic knotwork, lead-glass windows, Baccarat crystal doorknobs, elaborate moldings, bowed walls, chandeliers galore and luxurious bathrooms complete with stained glass, windowsills and balconies.

The Thomas survivors got the building back long enough to sell it to the adjoining St. Dominic’s Catholic Church for only $10,000. The second remodeling came when current owner Barbara Hathaway purchased it from the church in 1994 and pumped $200,000 into modernization.

The basement has a classic billiard room, with a vintage pool table complete with leather pockets. The first floor has a sitting room, dining room, porch (all breakfast options) and a hospitality room with (honest to God) complimentary decanters of brandy, port and some unidentified red liquid, surrounded by cut glass and an ice bucket.

Our “suite” boasted a bathroom bigger than my bedroom, a bedroom bigger than my first floor, a sitting room with a couch, magazines and a small library leading to a private deck.

You heard me.

The inn’s second floor contains the other rooms and the third floor has a cupola, which looks down on the Portland waterfront. In case the stars are not out, the cupola ceiling has a painted skyscape, complete with a full moon.

The possibilities of amusement are endless. The first night we walked to one of the approximately 3,000 restaurants in the area, the Katahdin on Spring Street. I had incredibly fresh halibut, pan-seared to perfection. She had better-than-average pasta. The vodka and tonic was as flat as pre-Columbus Earth, but we plowed ahead with the house chardonnay, and after a leisurely walk back to the Danforth, it was brandy under the stars.

Breakfast came with a grueling decision. Where would we enjoy the baked eggs with spinach and cheese along with a pineapple crisp, and assorted freshly baked (still warm) rolls, banana bread, croissants and assorted muffins? We chose the sunny porch.

Blue Eyed Susan is on the Olympic shopping team so we toured every merchant in the Old Port before we finally reached the Portland Museum of Art, which offered Rodin and Moore sculptures, Renoir and Degas paintings and of course the Wyeth and Homer Maine landscapes.

By then I needed a wheelchair.

We faded and went back to the room in order to prepare for the Saturday evening meal at our latest discovery, the Back Bay Grille. With money as no object (like it ever is) I started with the Baker single-batch whiskey and looked over the wine list, at least two pages longer than the Steven King opus “The Stand.” We split the salad (assorted greens, candied walnuts and goat cheese), skipped the appetizers and went right into the main course. I chose the sage chicken with risotto, she went with hand-rolled fettuccini with mushrooms and peas, being a born-again vegetarian.

Neither of us finished the meals, but you cannot leave a great restaurant and not order dessert, even if you don’t eat it. You have to check it out. We had the three-almond ice-cream tuile wedge, topped with banana mousse in a cannoli and drizzled with exquisite chocolate sauce. The dessert alone was worth the trip.

Properly stuffed, we rejected the 3,568 options that Portland night life offers and waddled back to the Danforth to try to digest the meal. We had our brandy in the cupola and decided this was the best time we ever had and everything else will be downhill.

So what if it was a $600 weekend, less the gift certificates? When and if you are required to assemble the Perfect Weekend, to prolong or preserve an important relationship, consider this painstaking research and damn the expense – especially if the asteroids are getting even closer.

Remember the Cobb Manor Motto:

Charge it!