A 40,000-square-foot, Richard Landry-designed megamansion in Bel Air, this recently completed spread was rumored to be asking $150M in November. Named the 2011 Ultimate Home by The Robb Report, the mansion has 28 bedrooms, "a full-service spa, a bar wrapped in Italian leather, a master suite coated in white onyx and bleached zebrawood," and "a custom "spinelike" helix staircase that weaves through the main house's four floors."

Owlwood, the 9.86-acre estate now owned by billionaire widow Dawn Arnall, is one of the largest in Beverly Hills, so, naturally, it should be one of the most expensive. It is. In late July, it was rumored that Arnall was quietly shopping the property around for $150M. A star-studded provenance, a 12,000-square-foot Tuscan-style mansion, and a border with the tony Los Angeles Country Club all contributed to that astronomical asking price.

Real estate investor Jeff Greene made himself a billionaire off the sub-prime mortgage crisis and proceeded to plunge some of that fortune into this insane Beverly Hills compound. In July, rumors began circling that Greene was ready to sell, albiet for the sky-high price of $150M.

The CitySpire building in NYC's Midtown might not have the cache of 15 Central Park West, but a triplex penthouse with 360-degree views is trying for the big money anyway. The 8,000-square-foot apartment has 3,000 square feet of outdoor space and was listed in July for $100M.

Listed by steel magnate Leroy Schecter in August, this $95M combination occupies a full floor at the hyper-expensive 15 Central Park West and includes the former rental apartment of Yankees star Alex Rodriguez.

The owner of this penthouse atop the Ritz-Carlton hotel on Manhattan's Central Park South stands to make a huge profit if he or she achieves the $95M asking price. Purchased in 2006 for just shy of $20M, the parkfront aerie recently underwent a $7M renovation.

A 266-acre waterfront estate with 1,100-feet of waterfront and a large pond came to market on Martha's Vineyard in July, with an asking price of $92M. The current owner, who purchased the property in the early 1990s, lives on a 50-acre plot nearby and never developed this larger tract.

Businessman Gabriel Brener, owner of the Houston Dynamo soccer team, built this sprawling megamansion on the site of Walt Disney's last home (and the entertainment guru's extravagant train set.) The 3.7-acre estate includes "eight-bedroom, 17-bathroom main house, a wine cellar, a pool house, a tennis court, a putting green, a screening room, three bars, a library, a gym, three inch thick mahogany doors, and two safe rooms."