Hi Christina

At a first glance I think your example looks right but I'm wondering if you perhaps need to cast the nodeId to be an int. Could you please try writing it like my example below?

    @inherits Umbraco.Web.Mvc.UmbracoViewPage<ContentModels.Activities>
    @using ContentModels = Umbraco.Web.PublishedContentModels;

    @using Umbraco.Web;

@{ 
  @* Cast the nodeId to an int here *@ 
    var nodeId = Model.GetPropertyValue<int>("nodeId"); 
   }

    @if (nodeId != null)
    {

        var page = Umbraco.TypedContent(nodeId);

        foreach (var child in page.Children)
        {
            <a href="@child.Url">@child.Name</a>
        }
    }
}

Does this help?

/Jan