A group of homeless people came in off the cold Manhattan streets Monday to feed their souls with a yoga class at an East Side shelter.

Her homeless students appeared apprehensive and some were reluctant to remove their shoes as the session of muscle stretching poses started. But by the end of the class, the five participants were peacefully chanting “Om” and most said they felt a calmness coursing through their weary bones.

“I know tenants have money—in the past some have given me $400,” says one doorman* who works at a historic building on Park Avenue at 62nd Street. “The lowest tip is usually $20. But we’re preparing for tips to be even lower this year.” In an effort to generate larger gifts, staffers say they’re scurrying to deliver packages with a smile. But they’re also employing intimidation tactics.

She’s probably right. At a luxury building at Fifth Avenue and 60th Street, the shop steward says, “Anything under $50 is considered a bad tip. Some tenants give $20, a few give $400 and some don’t give at all—and I can tell you the staff treats [the nongivers] differently. If a bad-tipping tenant calls down for help, the doormen make them wait a little longer. The biggest tippers get the best service.” The doorman of a chichi co-op at Park Avenue and 55th Street says that while even chintzy tippers get bare-bones service, he’s developed tactics for exacting revenge: “Let’s say you pull up in a cab with a bunch of packages. Maybe I’ll just happen to be on the phone.”

First they heard a ferocious rumble coming down Jewett Avenue; then came the crash of glass and a spray of ice.

By the time he ran outside to try and figure out what had happened, Pepe said the truck was already more than a block away: “He was going so fast, he probably did not even know what happened.”

The NYPD is making an unusual move to ensure no one notices a decline in the number of cops on the streets — decking out the vehicles used by traffic-enforcement agents, auxiliary police and school-safety agents so they look like regular cruisers.

In all, there are about 100 cars used by the auxiliary wing of the department and 200 used by each of the school-safety and traffic-enforcement divisions.

Bernard Madoff’s investors have lost everything, but his son and daughter-in-law seemed without a care in the world yesterday as they dashed around SoHo on a holiday shopping spree.

Andrew and wife Deborah, 41, who live on the Upper East Side, also shopped at American Eagle and a high-end lamp store, and checked out the windows at Vera Wang.