Possible Clues:

• Put on important hat for the races
• Races by contestants at a fete perhaps
• Put on important match between local teams -- event at fete, maybe
• Form of race
• Race for asses?
• Put on hat to introduce main event at fête, perhaps
• Assume opener and bowler create fair contest
• Important to wear hat going outside for race
• Riding race
• Asinine event put on, supported by important Victorian politician