Daya Nueva is a small inland town near Torrevieja, and its September fiesta is the sort of thing you stumble into rather than queue for. It builds slowly over a fortnight, then hits full tilt around the 29th. The standout is the mascletá: a midday wall of firecrackers you feel in your chest rather than just hear, followed in the evening by the saint's procession through the streets behind the local band.
There's a real spread of stuff going on. A flower-and-fruit offering, children's theatre and traditional games, a float parade, and a paella competition on the 30th where the town cooks lunch out in the recreational area. Most of it spills across Plaza de Espana and Calle Mayor, and it's free to wander into. Come hungry, expect noise, and don't plan an early night.