How do I add a new form that requires code-behind functionality?

I'm wanting to add a Questionnaire form.  I've already got the topic set up, the Localization set up, and I added it to the left info block via infoblock.ascx.

So I can directly edit the content on this via Content Management --> Topics, but I'm needing "code-behind" functionality.  How would I do this???  Thanks..

I actually answered my own question.

I created an iframe within the HTML code of the Topic itself.
I created a separate web form (aspx and aspx.cs), which the iframe uses as it's source.

On this separate web form I'm able to do what I want server side, client side, etc.