Are you coming from VB.NET and wondering if you can use these controls?
The answer to that is yes. You can use the Ajax toolkit in both VB.NET or in c#. You can also use jQuery UI which has (IMO) a slicker convention for theming and a huge plugin community.
If you're talking about for WinForms apps, yes, there's a DateTimePicker there as well. If you're interested in how it works, you can poke around with
Reflector[
^].
Cheers.