To amuse oneself
entertain oneself, revel, make merry, carouse, play games, rejoice, have a good time, idle away, horse around*.
Antonyms mourn*, grieve, sulk.
To gambol
frisk, sport, cavort, joke, dance, romp, frolic, play games, make jokes, be a practical joker, jump, jump about, skip, frolic, caper, cut capers*, cut up*, show off*, be the life of the party*, play the fool*, carry on*.
Antonyms drag*, mope, droop.
To produce music
perform, execute, operate, work, cause to sound, finger, pedal, bow, plunk, tinkle, pipe, toot, mouth, pump, fiddle, sound, strike, saw, scrape, twang, pound, thump, tickle.
To display light, erratic movement
waltz, spout, flicker; see dance 1, 2.
To act in a play
impersonate, present, represent; see act 3, perform 2.
To engage in sport
participate, engage, rival; see compete, contest 2.
To pretend
imagine, suppose, think; see pretend 1.
To gamble
chance, risk, hazard; see gamble 1.