Pieces required to enable MVC client side validation with Bootstrap themes. Assumes you are using the 'control-group' and other elements from the Form examples in the Bootstrap tutorials (form-horizontal only for now).

BootstrapHtmlExtensions.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;


namespace System.Web.Mvc.Html
{
	public static class TwitterBootstrapHelperExtensions
	{
		//http://stackoverflow.com/questions/7215477/best-approach-for-extending-unobtrusive-javascript-in-mvc3-to-add-a-style-to-a-d
		public static MvcHtmlString BootstrapValidationSummary(this HtmlHelper helper,
							   bool excludePropertyErrors,
							   string message)
		{
			if (helper.ViewData.ModelState.Values.All(v => v.Errors.Count == 0)) return new MvcHtmlString(string.Empty);

			string errorsList = "<ul>";
			foreach (var error in helper.ViewData.ModelState.Values.Where(v => v.Errors.Count > 0))
			{
				errorsList += string.Format("<li>{0}</li>", error.Errors.First().ErrorMessage);
			}
			errorsList += "</ul>";
			return new MvcHtmlString(string.Format("<div class=\"alert alert-block alert-error\"><strong>{0}</strong>{1}</div>", message, errorsList));

		}
	}
}

jquery.validate.bootstrapmvc4.js

//http://pknopf.com/blog/twitter-bootstrap-clientside-validation-with-jquery-validation-js
//http://stackoverflow.com/questions/7215477/best-approach-for-extending-unobtrusive-javascript-in-mvc3-to-add-a-style-to-a-d
(function ($) {
	$.validator.setDefaults({
		highlight: function (element) {
			$(element).closest('.control-group').addClass('error');
		},
		unhighlight: function (element) {
			$(element).closest('.control-group').removeClass('error');
		}
	});
	$('span.field-validation-valid, span.field-validation-error').each(function () {
		$(this).addClass('help-inline');
	});
	$('form').submit(function () {
		if ($(this).valid()) {
			$(this).find('div.control-group').each(function () {
				if ($(this).find('span.field-validation-error').length == 0) {
					$(this).removeClass('error');
				}
			});
		}
		else {
			$(this).find('div.control-group').each(function () {
				if ($(this).find('span.field-validation-error').length > 0) {
					$(this).addClass('error');
				}
			});
		}
	});
	$('form').each(function () {
		$(this).find('div.control-group').each(function () {
			if ($(this).find('span.field-validation-error').length > 0) {
				$(this).addClass('error');
			}
		});
	});
}(jQuery));

Can we get a code snippet it on how to implement this code? please