A " a variant of flash mob, is an event in which a large group descends on a small business with each person prepared to spend a predetermined amount of money there. One will be held in Sag Harbor on May 6. Meet at the Sag Harbor Windmill at 3 p.m. Participants won't be told what business they're headed to until they arrive. Post-mob, the participants are invited to for an after-party with drink and appetizer specials.