<p>I want to recreate the the update panel postback without using an update panel to do the postback.  What is the generic method for doing this?</p>

<p>For example, on Stackoverflow, when you vote up or down on a question it does a postback to update the database and I would bet they didn't use an update panel.</p>

<p>What do I have?</p>

<p>I have a table with table data.  When I click on the <code>td</code> item as a whole column, I want to do an update to the database and also update a gridview on the page itself.  The gridview shows all the currently clicked items in the table because it was updated via "our method".</p>

<p>Looking for a good generic method I could use for a lot of async postbacks without update panel.</p>

You can just use a standard AJAX call to accomplish this.  Create a .aspx page which updates the database in its Page_Load method, and displays any desired information (like the current DB value after the update) as XML.  Then make an AJAX call to that page using jQuery.
You can also return an HTML fragment (i.e. an updated GridView), and use jQuery to insert the updated HTML into the current page.
Edit:
Sample 2 on this page should be very close to what you want:
http://www.codeproject.com/KB/ajax/AjaxJQuerySample.aspx