I was reading the MSDN documentation about Conversation Window Extensions and all of the examples that I found require working with IIS. Is there some way to create a CWE without using IIS?
Can I create a CWE for Lync 2010 without working on HTML?
A Conversation Window Extension must either be Silverlight or HTML - Silverlight is preferred as this gives you access to the Lync SDK.
There is no reason why they have to be hosted in IIS - you could have the Silverlight Xap file and the host HTML file on your local drive, and point Lync to this via the registry settings.
To try this out, install the Lync SDK and create a new Lync Silverlight Application. When you get prompted, uncheck the box to create a new website. Go into the Page.Xaml - there will be a PresenceIndicator control on the page - change the URI property to the URI of one of your contacts.
Then build the app, and go to the output directory (bin/debug) - among other files, there should be a .Xap file and a TestPage.html.
Create your registry settings according to this article, using the location of the TestPage.html file as the InternalURL and ExternalURL properties, e.g.
file://S:\Testing\LyncSilverlightApplication2\LyncSilverlightApplication2\Bin\Debug\testpage.html
Restart Lync, start a new conversation with anybody, and then select your app from the "More Options" menu (>>). The Silverlight app should be displayed as a CWE.