The Razor engine HTML encodes strings by default, as you have noticed. To avoid this behavior, just use Html.Raw()
:
<ul>@Html.Raw(List)</ul>
Edit
To render a variable within a string, I suppose you could use string.Format
:
@{ var someVariable = "world"; }
@string.Format("<div>hello {0}</div>", someVariable)
Although that seems like overkill (at least for this example) when you can just write:
<div>hello @someVariable</div>