a very simple feature i implemented today was to make an IE only style sheet for my application i'm writing it only took 2 lines to make it work. Firstly put the following line in your asp page (best place would be a master page):
<link href="Styles/IEStyle.css" rel="stylesheet" type="text/css" runat="server" id="lnkIEStyle" visible="false" />
this should go after any other style sheets so that it's content takes precedence over the other style sheets.
Secondly put the following line of code (it is in C#) in your page load:
lnkIEStyle.Visible = Request.UserAgent.Contains("MSIE");
this works very well and you can easily make your website look the same across numerous browsers and the method could be used for different browser detection such as if the user agent string contains "gecko" you could single out mozilla based browsers.