The example here illustrates how to AJAX-enable the standard MS Timer control with RadAjaxManager. Note that you cannot add the Timer control directly to the AJAX settings as an updated control. Instead, you need to wrap the timer in a container like ASP:Panel and set the container as the updated control.
The example also demonstrates continuous update of RadGrid per certain interval. This however can be achieved by binding the Grid client or server-side through Web Service. See the articles in the Related Resources tab for additional information.