If you, like me, own the best mobile phone in the universe, the Nokia Lumia 920, and design websites, you might have noticed that responsive sites are not responsive on this device.

This is a IE10 bug. To fix this, you should include the following snippet in the head (or wherever really) of your index file.

if (navigator.userAgent.match(/IEMobile/10.0/)) {
    var msViewportStyle = document.createElement("style");
    msViewportStyle.appendChild(
        document.createTextNode(
            "@-ms-viewport{width:auto!important}"
        )
    );
    document.getElementsByTagName("head")[0].
        appendChild(msViewportStyle);
}

I don’t remember where I got this one, so no credits or reference, but it works!