Madonna Was Havana Great Time Dancing on Bars for Bday

Madonna likely sparked a Cuban missile crisis in some guy's pants when she started bumping and grinding for her birthday celebration in Havana.

Madge was tearing it up in a bar called La Vitrola ... dancing on the bar by herself for several minutes until the chico joined her. The crowd, and her dance partner, were LOVING it.

16-year-old Rocco was also there for the party -- and joined Mom for some far more appropriate salsa dancing.

Gotta say ... Madonna almost makes 58 look fun, instead of just plain old.