Because this blog is more like a glorified scratch pad that I won't lose, this is what to do when:
A file you know exists, but you get 404s
Fonts are coming up (see above)
YOu have a new project and you know that you want to support files that your server (IIS) might not know about. (Remember, all files have a mime type that needs to be mapped. This example is for fonts, but could be mp4s or whatevs).
Add this to the web.config:
<system.webServer>
<staticContent>
<mimeMap fileExtension="woff" mimeType="application/font-woff" />
<mimeMap fileExtension="woff2" mimeType="application/font-woff" />
</staticContent>
</system.webServer>