WordNet (r) 3.0 (2006):

shenanigan
    n 1: reckless or malicious behavior that causes discomfort or
         annoyance in others [syn: mischief, mischief-making,
         mischievousness, deviltry, devilry, devilment,
         rascality, roguery, roguishness, shenanigan]
    2: the use of tricks to deceive someone (usually to extract
       money from them) [syn: trickery, chicanery, chicane,
       guile, wile, shenanigan]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "shenanigan":
   antic, caper, device, fast one, frolic, game, gimmick, goings-on,
   lark, legerdemain, maneuver, mischievousness, monkeyshine, play,
   ploy, ruse, shines, stratagem, stunt, tomfoolery, trick, whizzer,
   wile