<p>Anyone know a good Regex expression to drop in the ValidationExpression to be sure that my users are only entering ASCII characters?  </p>

<pre><code>&lt;asp:RegularExpressionValidator id="myRegex" runat="server" ControlToValidate="txtName" ValidationExpression="???" ErrorMessage="Non-ASCII Characters" Display="Dynamic" /&gt;
</code></pre>

If you want to map the possible 0x00 - 0xff ASCII values you can use this regular expression (.NET).
```
```
^([\x00-\xff]*)$
```
```