Area office buildings sprout 'for-sale' signs. (Denver, Colorado)

Something big's happening in the Denver office market. The planets have aligned, or the market's mojo has kicked in, or the gods are smiling, spurring a flood of office buildings to sprout "for-sale" signs.

Just looking at larger structures, 10 properties encompassing almost 3 million square feet seek new landlords. Newly swept into the office-building derby reportedly are the Aurora Corporate Plaza and Ptarmigan Place, two premium properties that together sprawl over almost 750,000 square feet.

Other significant office properties have already sold this year, including the 138,000-square-foot Meridian One, U S West Inc.'s last local building, which just went for $9.5 million, or $69 a square foot.

Purchasers of Class A metro-area buildings have forked over $70 to $120 a square foot since the …