You can use MSHTML, which can be pretty forgiving;
//using microsoft.mshtml
HTMLDocument htmldoc = new HTMLDocument();
IHTMLDocument2 htmldoc2 = (IHTMLDocument2)htmldoc;
htmldoc2.write(new object[] { "<p>Plateau <i>of<i> <b>Leng</b><hr /><b erp=\"arp\">2 sugars please</b> <xxx>what? & who?" });
string txt = htmldoc2.body.outerText;
Plateau of Leng 2 sugars please what?
& who?