A party within a party. Ten tickets to The Radiators June 21 performance, part of this summer’s Rock and Blues Cruise Concert Series. The Radiators combine the traditional music of their hometown, New Orleans, with mainstream rock and R&B to create a unique, Swamp-Rock sound. Guests will board the Frederick L. Nolan on Long Wharf, adjacent to New England Aquarium, at 7:30, for an 8:00 p.m. departure.