It is organised by Oranje Fonds, and tasks are offered up by groups and listed online by type and location so that volunteers can be matched to jobs that need doing in their area. Tasks are varied and include things like gardening, supervising special needs groups in special activities, renovations, helping out at the local city farm and painting.
The action coincides with "Landelijke Opschoondag", which is another volunteer initiative to get people out to clean up their neighbourhoods.
Dutch celebrities, royals and ministers are also on the list of volunteers to take action, so you are in good company if you join in on Friday 19 and/or Saturday 20 March.
Whether you are an individual, a family or part of a volunteer group, school or company and want to get involved then check out http://www.nldoet.nl/nldoet. If there are 25 or more of you available, you can make a specific search for jobs so you can work as a team - how's that for a company activity?