Other forms: doubleheaders
When two baseball games are played in a row, one right after the other, that's a doubleheader. Last week's game was called off because of rain, so today they're playing a doubleheader.
You can use this term for any sporting events, but it originated with baseball. It was once common for a few baseball doubleheaders to be scheduled throughout the season, but today this generally happens only when a previous game had to be postponed. Strictly speaking, doubleheaders occur in succession, one immediately following the other, but the term is often used for any two games played in one day by a single team.