Using custom grid partial
Name Surname Marital status Age Birthday Employed
Joe Crosswave Married 36 1/5/1988 False
Child name Age Birthday
Katy 9 1/5/2015
Kate 9 1/5/2015
Merry Lisel Widowed 46 5/6/1978
Henry Crux Single 34 11/19/1990 True
Cody Jurut 54 8/11/1970 False
Simon Scranton Single 39 10/10/1985
Leena Laurent Divorced 24 7/1/2000 False
Ode Cosmides Married 58 4/17/1966 True
Child name Age Birthday
Jake 10 7/14/2014
Diandra Mizner Single 25 8/20/1999 False
Pete Cassel Married 27 3/13/1997 False
Nicky Tremblay Married 36 1/5/1988 True
Child name Age Birthday
Nick 11 6/8/2013
Nike 9 12/12/2014
Norbert 9 5/23/2015
View 

@model IQueryable<Person>

@(Html
    .Grid("_NestedPersonGrid", Model)
    .Build(columns =>
    {
        columns.Add(model => model.Name).Titled("Name");
        columns.Add(model => model.Surname).Titled("Surname");
        columns.Add(model => model.MaritalStatus).Titled("Marital status");

        columns.Add(model => model.Age).Titled("Age");
        columns.Add(model => model.Birthday).Titled("Birthday").Formatted("{0:d}");
        columns.Add(model => model.IsWorking).Titled("Employed");
    })
)
_NestedPersonGrid partial view 

@model IGrid<Person>

<div class="mvc-grid">
    <table>
        <thead>
            <tr>
                @foreach (IGridColumn column in Model.Columns)
                {
                    <th>
                        <span class="mvc-grid-title">@column.Title</span>
                    </th>
                }
            </tr>
        </thead>
        <tbody>
            @if (Model.Rows.Any())
            {
                foreach (IGridRow<Person> row in Model.Rows)
                {
                    <tr class="@row.CssClasses">
                        @foreach (IGridColumn column in Model.Columns)
                        {
                            <td class="@column.CssClasses">@column.ValueFor(row)</td>
                        }
                    </tr>

                    if (row.Model.Children.Any())
                    {
                        <tr>
                            <td colspan="@Model.Columns.Count()">
                                @(Html
                                    .Grid("_NestedPersonGrid", row.Model.Children)
                                    .Build(columns =>
                                    {
                                        columns.Add(model => model.Name).Titled("Child name");
                                        columns.Add(model => model.Age).Titled("Age");
                                        columns.Add(model => model.Birthday).Titled("Birthday").Formatted("{0:d}");
                                    })
                                )
                            </td>
                        </tr>
                    }
                }
            }
            else
            {
                <tr class="mvc-grid-empty-row">
                    <td colspan="@Model.Columns.Count()">
                        @Model.EmptyText
                    </td>
                </tr>
            }
        </tbody>
    </table>
</div>