Prank, caper, antic, monkeyshine, dido mean a playful, often a mischievous, act or trick.
Prank carries the strongest implication of devilry of all these words, though there is little suggestion of malice and primary emphasis upon the practical joke.
Caper can suggest carefree frisking and bounding like a kid and is especially applicable to capricious or reckless escapades.
Antic stresses the ludicrousness and grotesqueness of the movements, gestures, and postures rather than the spirit in which the acts or tricks are performed.
Sometimes, however, it suggests showing off.
Monkeyshine may be applied to a caper or antic, but, especially in the plural, the term typically applies to behavior or a trick that attracts attention by its inappropriateness and often impropriety.
Dido, also frequently used in the plural, applies to an absurd, foolish, or mischievous act and may come close to monkeyshine in suggesting obtrusive inappropriateness.