Photo by D Dipasupil/FilmMagic.

A note to our colleagues: Now may be a good time to stop sleeping in the office. Mayor Michael Bloomberg had The Observer on his mind yesterday at the Friends of the Hudson River Park's sping gala, reminding partygoers that FOHRP board chair Douglas Durst ranked fifth on The Commercial Observer's Real Estate Power 100, five spots ahead of hizzoner. "Look out for a visit from the city's building inspectors," he quipped, a friend tells us.

Mr. Bloomberg—his girlfriend Diana Taylor chairs the board of the Hudson River Park Trust—was on hand at Pier 26 to present Highbridge Capital co-founder Glenn Dubin with the FOHRP's Leadership in Community Enrichment award. It was no mere pit-stop on the evening agenda—Mr. Bloomberg stayed through dinner (goat cheese panna cotta and seared arctic char from Union Square Catering) and chatted with guests (who included Christy Turlington, Ed Burns and former-Gov. George Pataki).

Teen-aged children mean Mr. Dubin—who grew up in Washington Heights and frequented Fort Tryon Park as a boy—is spending less time at his country house these days, he told guests, and more time in the park. Though Mr. Dubin seemed partial to venerable Central Park, his track record as a philanthropist—Mr. Dubin was a founding board member of the Robin Hood Foundation, and more recently, the Eva and Glenn Dubin Breast Care Center at Mt. Sinai Hospital—and environmentalist instincts made him an apt honoree.

"You're looking for someone who can raise money, yes, but also someone whose ethos matches what the organization is trying to accomplish," said Michael Novogratz, a principal at Fortress Investment Group and Hudson River Park Trust board member. Mr. Dubin's stature on Wall Street helped bring fresh faces to the sold-out event, said FOHRP executive director A.J. Pietrantone, and the organization treated guests to cameos by park users. Intrepid members of New York Kayak Water Polo staged an exhibition off Pier 26 during the cocktail hour, and CBS This Morning co-anchor Gayle King—who hosted the festivities—was escorted onto the stage by a parade of dog-walkers. Mr. Durst entered by bicycle. "We wanted to give our guests the sense of fun and exploration that's at the heart of what Hudson River Park is all about," Mr. Pietrantone said.

The event raised $1.6 million towards the park's operating fund. Guests gossiped that a generous donor had made a $50 million pledge, but Mr. Pietrantone said that the organization hadn't received a gift at that level.

As The Observer noted at the time, it took the Dubins nine months to bring their home to market, and now twice as long to sell it, and at quite the discount, no less.

The duplex, which looks down on the Met, just sold for $13.75 million to another budding banker, Alexander Klabin, who runs Senator Investment Group. According to an article in Absolute Return + Alpha, the fund is having Dubin-esque success, "thriving at a time when most new funds are finding it difficult to raise funds." The firm has won seed money from the Blackstone Group and manages more than $2 billion in funds. How long before he serves atop the Robin Hood Foundation, or some other prestigious New York charity, as Mr. Dubin once did?

Mr. Klabin bought the six-bedroom, five-and-a-half bath home that the Dubinz assembled over a number of decades with his wife Kristin, a former middle school teacher. The 12-room whopper is a beaut, as Corcoran star Deborah Grubman makes clear in her listing: "Excellent condition - Central Park Views - West and South facing views from major rooms - Full Service, White Glove Building." Carter Horseley puts things a little more grandiloquently in his description of the 1928 Fred F. French building: "With its handsome Italian Renaissance-style detailing, sidewalk landscaping and attractive sidestreet entrance, 1010 Fifth Avenue is one of the classic elegant addresses in the city."

The Klabins are leaving behind a decidely different home as they depart the glassy, four-year-old condo tower at 255 East 74th Street.

Besides Mr. Dubin (No. 773 on last year's Forbes rich list), other notable residents at 1010 Fifth include Richard Kalikow and Anthony "Tommy Bahama" Margolis, whose eighth-floor three-bedroom has been on the market for more than three years and is currently asking $10.25 million. The building is across from the Duke Semans Mansion, which Carlos Slim (No. 1 on said list) bought last year for $44 million, the most expensive sale of 2010.

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mchaban [at] observer.com | @mc_nyo