• Iris Cantor, the widow of Cantor Fitzgerald founder Bernie Cantor, has gone into contract to sell her penthouse at 110 Central Park South. The four-bedroom pad, which Cantor bought for $15 million in 2006, had been listed recently for $11.9 million. [NYO]
• Pro golfer Cristie Kerr and her husband, Aviator Sports president Erik Stevens, have picked up an 11th-floor condo at One Morton Square. The couple paid $2.3 million for the three-bedroom pad. [Cityfile]
• Hedge funder Steve Eisman has unloaded his nine-room apartment at 1125 Park Avenue for $5.2 million, or $1.795 million less than what he paid for it in March 2008. Eisman can afford to take the loss. His Front Point Partners is believed to have made a fortune betting against subprime lending. [NYO]

Twins Charlotte and Samantha Ronson turn 32 today. David Duchovny is turning 49. Charlize Theron is 34. Author and radio personality Garrison Keillor is 67. Conservative political commentator Alan Keyes turns 59. Wayne Knight, the actor best known for playing Newman on Seinfeld, is turning 54. And Jimmy Wales, the co-founder of Wikipedia, is 43 today—at least according to his Wikipedia page. A handful of weekend birthdays—including that of Michael Kors, Chris Cuomo and Dustin Hoffman—follow below.

Celebrating birthdays today: Real estate broker Deborah Grubman—who also happens to be the wife of Allen and stepmom of Lizzie—turns 56. Party planner extraordinaire David Monn is 45. Designer John Varvatos turns 54. Dustin Hoffman is 71. Two former boy band-ers, Drew Lachey and JC Chasez, both turn 32 today. Tennis star Roger Federer is 27. And Robin Quivers is 56. Saturday is the big day for Chris Cuomo (left) who will be celebrating his 37th. Michael Kors will be turning 49. Allure's Linda Wells will be 50. And real estate broker Larry Kaiser and designer Peter Marino will be a year older on Saturday, too. On Sunday: Fashion icon Betsey Johnson will be 66, actress Angie Harmon will be 36, and real estate developer Harry Macklowe will turn 71.

One of the city's elite co-op brokers—he's sold more than ten apartments in 834 Fifth alone—Kaiser runs Key-Venture Realty, a small residential brokerage previously controlled by his mother. His clients have included crooner Neil Diamond and fashion tycoon Kenneth Cole.