The Holly Jolly Run in Fountain Valley, CA, is a festive, family-friendly event held at Mile Square Park. Participants can enjoy different races, including a 5K, 10K, and shorter dashes, all in a holiday-themed atmosphere with jingle bells for shoes and seasonal treats. The event features Santa sightings, holiday music, and photo opportunities, with goodie bags for kids and awards for top finishers. Parking is available for a fee, and the event goes on regardless of weather conditions, encouraging participants to dress festively and enjoy the community spirit.