On Sunday night, nearly 150 patrons crowded into the ground floor of OM Restaurant and Lounge—but unlike any other night, jazz emanated from the lounge, as customers gathered to support earthquake victims in Haiti.

Though the Harvard Square Business Association has not formally organized a fundraising campaign, individual businesses around the Square—such as OM—have started their own fundraising projects to support the devastated nation.

The event at OM raised $6,300 through a $20 cover charge and donated proceeds from select menu items, according to Rahim B. Kanani, a research associate at the Hauser Center for Nonprofit Organizations.

In a similar effort, Upstairs on the Square—located across from OM—made between $25,000 and $28,000 during its day-long fundraiser on Monday. Proceeds from breakfast, lunch, and dinner at the restaurant were donated to Partners in Health, a Harvard-affiliated nonprofit that operates community-based clinics in Haiti and eight other countries, according to owner Mary-Catherine Deibel.

The fundraising event at Upstairs—which attracted about 500 people throughout the day—was held in place of the restaurant’s post-holiday staff party.

But local restaurants were not the only businesses to raise money for Haiti. The José Mateo Ballet Theatre held “Dance for World Community: a benefit for earthquake relief in Haiti” last Saturday, raising $8,000 for the Haiti Fund at the Boston Foundation, which will match that amount for a total of $16,000.

And while folk music venue Club Passim has plans to hold a benefit concert next Tuesday, Rick Fogarty, owner of Plan B Cut and Color Boutique, said he is matching 20 percent of all pledges for Haiti made through his salon’s Facebook fans.

In addition to businesses hosting single-day events, The Charles Hotel, Qdoba, Via Vai, and ALO have all pledged longer-term fundraising campaigns.

At the Charles Hotel and its outlets—which include Henrietta’s Table, Rialto, Noir, and the Regattabar—customers have been given the option of adding a one-time donation to their checks. Customers have so far donated more than $12,000, according to Rebecca H. Fetner, Rialto’s public relations and marketing manager.

Aside from encouraging patrons to donate, Rialto is also donating all of its proceeds from vegetable side dishes to PIH. Rialto’s diners have been purchasing more vegetable side dishes than usual, Fetner said, adding that the restaurant has netted more than $1,500 in donations from vegetable side dishes.

Proceeds from soda sales at Qdoba will go to Haiti relief efforts. For the entire month of January, the restaurant will donate one dollar to the International Red Cross for every large soda purchased.

—Staff writer Kerry K. Clark can be reached at kclark@fas.harvard.edu.

This article has been revised to reflect the following correction:

CORRECTION: January 28, 2010

An earlier version of the Jan. 28 news article "Square Businesses Support Haiti" stated that the special event at OM Restaurant and Lounge was held on Saturday. In fact, it occurred on Sunday.