For the entire next season, the loser writes and posts a weekly poem summarizing the league's results, praising the week's winners and mocking themselves as required. Meter and rhyme standards are enforced by public criticism. Skipped weeks roll over with interest.
The long haul: this is not a one-afternoon sentence. With a time commitment of full season, 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.
Seen in the wild: fantasypunishments.com