Use this code in the markup to highlight the current day in a DatePicker control.
<sq:DatePicker runat="server" ID="Field2" >
<Calendar>
<SpecialDays>
<sqr:RadCalendarDay Repeatable="Today" ItemStyle-CssClass="rcToday">
</sqr:RadCalendarDay>
</SpecialDays>
</Calendar>
</sq:DatePicker>