The loser wears an engraved pendant or chain displaying the logo of their failed team, or the word 'LOSER', at every league event, and in strict leagues daily, until relieved by a new loser. One documented league runs a Detroit Lions pendant with accumulating engravings. Jewelry as sentence.
The long haul: this is not a one-afternoon sentence. With a time commitment of full year, the punishment keeps paying out (for everyone else) long after the season ends. Long sentences need a written end date and a league-appointed enforcer who checks compliance.