The Collaborative International Dictionary of English v.0.48:
conga line \conga line\ n. 1. a line of persons dancing the conga[2]. [PJC] 2. a line of persons similar to a conga line[1]. Sometimes used figuratively or humorously. [PJC]WordNet (r) 3.0 (2006):
conga line n 1: a line of people in single file performing the conga dance