Hard to say with absolute certainty what the Mayans did and did not do. Pretty thick jungle down there.
According to Spanish sources, as well as frescoes and sculptures from the city of Tajin, the original form of the Mesoamerican game ulama included sacrifice of the entire losing team.
Mayans also held the belief that cenotes or limestone sinkholes were portals to the underworld and sacrificed human beings to please the water god Chaac. The most notable example of this is the "Sacred Cenote" at Chichen Itza where extensive excavations have recovered the remains of 42 individuals, half of them under twenty years old.