Originally spelled panbol (lit. bread-ball). Panbol was used pejoratively by Mexican snobs to refer to soccer ("the sport of bread bakers"). Nowadays it is spelled pambol or pambola and it is used in an affectionate way to refer to Mexicans' favorite sport (soccer, of course). It is not offensive in any way.
A person is said to be pambolero or pambolera if he or she is a fan of pambol. A thing is said to be pambolera if it is related to soccer (e.g. fiebre pambolera, soccer fever).
Lula (Brazil's President) gave Obama (U.S. President) and Calderón (Mexico's President) a jersey of Brazil's national soccer team autographed by all its players. By their reaction you can immediately tell who is pambolero.