Stats based on visits to on 13th July 2012 (total visits from website launch (~11am) till 9pm = 314).

Unobtrusive, factual notice displayed to users of Internet Explorer version 8 and below:

Note the failure of IE8 to render the design. HTML5 and CSS3 are the most recent versions. IE9 was the first browser to support them and this turned out horribly wrong because they were not at all complete and finalised when IE9 was released. Ipso facto, the amount of conflicts resulting from changes is colossal, not to mention the features that were added after IE9 was released.

Conditional statement. 'lte' = less than:

Note the message is only being displayed to users with IE8 or below. IE9 renders the website well enough to hide the warning, though there are a few problems that are caused by abovementioned issue.

Arts Theatre visitor usage in real terms (based on today's stats only):

IE makes up only 26.75% of visits, while modern browsers total 65.28%. The remainder are mobile browsers, which render the website fine.

IE visits, scoped down:

62% of the 27% are using IE 9, which renders the website fine.

Further Reading:
HTG Explains: Why Do So Many Geeks Hate Internet Explorer?
ELI5: Why is it considered so 'bad' to use Internet Explorer, & what is so great about the alternatives?
Why IE Sucks for Developers, Users, and Why it Still Won't Die - Extensive article, covering everything.