Prinsjesdag (English: Prince's Day) is the day on which the reigning monarch of the Netherlands (currently Queen Beatrix) addresses a joint session of the Dutch Senate and House of Representatives in the Ridderzaal or Hall of Knights in The Hague. The Speech from the Throne (Dutch: Troonrede) sets out the main features of government policy for the coming parliamentary session.
The Queen, normally accompanied by other members of the Royal House, leaves Noordeinde Palace in the Golden Carriage for the Binnenhof, escorted by court dignitaries and a military escort of honour. Outside the palace stand an escort of honour and a military band. (source:Wikipedia)
Prinsjesdag is traditionally on the third Tuesday in September
The day before Prinsjesdag the horses involved in the Royal riding tour undergo a training on the beach at Scheveningen in order to acquire stress resistance for their yearly performance.