Except for Saturday afternoon, the event takes place at Sportpark Sloten, Sloterweg 1045, 1066 CD, Amsterdam. From the Google maps link, you can plan your ride by bike, public transport or other means. The nearest metro station is Henk Sneevlietweg (2.3 km walk). If you take this route, the 7 km bike ride to/from the Amsterdam Zuid train station (OV-fiets available) is quite scenic. Parking is available inside the Sportpark, the barrier opens automatically.
Sportpark Sloten is located at a stone's throw from Schiphol airport, but you are not permitted to land your human powered plane there.

On Saturday we depart at 12:00 for Wheelerplanet Spaarnwoude, Zijkanaal C Weg 6-7, 2064 KA, Spaarndam. Google maps.