Oliebollentocht is probably the largest annual velomobile gathering in the world. It is organized by the Dutch group Grensrijder at the 28. of Dezember at varying locations.
This year, about 150 velomobile riders met in Roermond.
I couldn’t attend, since my Milan still isn’t roadworthy. Also, the 450km journey to Roermond would be a bit much for my current fitness level. My plan is to join Oliebollentocht 2019 in Utrecht.
Anyway, Helen wrote a very nice blog post with lots of pictures of her Oliebollentocht experiance: http://www.auntiehelen.co.uk/oliebollentocht-2018
and Josef shot some great video with a Garmin 360 Vibe mounted to his DF: