The Collaborative International Dictionary of English v.0.48:

Buffoonery \Buf*foon"er*y\, n.; pl. Buffooneries. [F.
   bouffonnerie.]
   The arts and practices of a buffoon, as low jests, ridiculous
   pranks, vulgar tricks and postures.
   [1913 Webster]

         Nor that it will ever constitute a wit to conclude a
         tart piece of buffoonery with a "What makes you blush?"
                                                  --Spectator.
   [1913 Webster]

WordNet (r) 3.0 (2006):

buffoonery
    n 1: acting like a clown or buffoon [syn: buffoonery,
         clowning, japery, frivolity, harlequinade, prank]

Moby Thesaurus II by Grady Ward, 1.0:

83 Moby Thesaurus words for "buffoonery":
   acting, asininity, banter, battiness, brainlessness, business,
   characterization, clownishness, crackpottedness, crankiness,
   craziness, daffiness, desipience, eccentricity, fatuity,
   fatuousness, folly, foolery, foolheadedness, fooling, foolishness,
   frivolity, frivolousness, gag, giddiness, goofiness, ham,
   hammy acting, harlequinade, hoke, hokum, horseplay, idiocy,
   imbecility, impersonation, inanity, ineptitude, insanity, lunacy,
   madness, mimesis, mimicking, mimicry, miming, mindlessness,
   monkeyshines, mummery, niaiserie, nugacity, nuttiness, overacting,
   pantomiming, patter, performance, performing, personation,
   playacting, playing, portrayal, projection, queerness,
   representation, sappiness, screwiness, senselessness, shenanigans,
   silliness, slapstick, stage business, stage directions,
   stage presence, stunt, stupidity, taking a role, thoughtlessness,
   tomfoolery, triflingness, triviality, wackiness, weirdness,
   witlessness, zaniness, zanyism