The Collaborative International Dictionary of English v.0.48:

Clumps \Clumps\, n.
   A game in which questions are asked for the purpose of
   enabling the questioners to discover a word or thing
   previously selected by two persons who answer the questions;
   -- so called because the players take sides in two "clumps"
   or groups, the "clump" which guesses the word winning the
   game.
   [1913 Webster]