It's that time of year again. MGM Mirage-- which now owns over half of the hotel rooms on the Strip-- is spending a whole lot of cash on its Vegas spring cleaning. $800 million on upgrades, in addition to the $7 billion they're shelling out for the Project CityCenter development, expected to open in 2010. After all, you've got to spend money to make money, as the Las Vegas Sun explains: "the idea is to continue to attract big spenders." Last year they spent big bucks on upgrading a wing of MGM Grand, building high-end Skylofts, adding two restaurants from Chef Joel Robuchon, and serious upgrades at Mandalay Bay. What's in store with this year's spring cleaning? Renovation of the outdoor pool and beach area at Mandalay Bay to add a bunch of new deck space and cabanas. Remodeling of the Rumjungle bar and revamping of the 3950 restaurant, with the addition of a celebrity chef. A new nightclub at Luxor. A new restaurant and bar at Excalibur. A new Japanese restaurant at Mirage. And the biggest upgrade of all: a Cirque du Soleil show inspired by the music of the Beatles, to debut in May at the Mirage.