Snipplet to create a minimal Friendly URL handler

protected void Application_Start(Object sender, EventArgs e)
{
    XFormControl.ControlSetup += new EventHandler(XForm_ControlSetup);

    EPiServer.Web.UrlRewriteModuleBase.HttpRewriteInit +=
         new EventHandler<EPiServer.Web.UrlRewriteEventArgs>(
             MyFriendlyURL.UrlRewriteModuleBase_HttpRewriteInit);

    EPiServer.Web.HtmlRewriteToExternal.HtmlRewriteInit +=
        new EventHandler<EPiServer.Web.HtmlRewriteEventArgs>(
            MyFriendlyURL.HtmlRewriteToExternal_HtmlRewriteInit);
}

using System;
using System.Text.RegularExpressions;
using EPiServer.Web;

namespace EPiServer
{
    public class MyFriendlyUrl
    {
        /// <summary>
        /// Handles the HttpRewriteInit event to initialize the
        /// UrlRewriteModuleBase control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EPiServer.Web.UrlRewriteEventArgs"/>
        /// instance containing the event data.</param>
        public static void UrlRewriteModuleBase_HttpRewriteInit(
            object sender,
            UrlRewriteEventArgs e)
        {
            UrlRewriteModuleBase module = sender as UrlRewriteModuleBase;
            if (module != null)
            {
                module.HttpRewritingToInternal +=
                    new EventHandler<UrlRewriteEventArgs>(
                        HttpRewritingToInternal);
            }
        }

        /// <summary>
        /// Handles the HtmlRewriteInit event of initializate the
        /// HtmlRewriteToExternal control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EPiServer.Web.HtmlRewriteEventArgs"/>
        /// instance containing the event data.</param>
        public static void HtmlRewriteToExternal_HtmlRewriteInit(
            object sender,
            HtmlRewriteEventArgs e)
        {
            MyUrlRewriter rewriter = new MyUrlRewriter();
            e.RewritePipe.HtmlRewriteUrl +=
                new EventHandler<HtmlRewriteEventArgs>(
                    rewriter.RewritePipe_HtmlRewriteUrl);
        }

        /// <summary>
        /// A handler to rewrite external URLS (friendly) the EPiServers
        /// native urls (with query srings).
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="e">The <see cref="EPiServer.Web.UrlRewriteEventArgs"/>
        /// instance containing the event data.</param>
        public static void HttpRewritingToInternal(
            object sender,
            UrlRewriteEventArgs e)
        {
            UrlRewriteModule module = sender as UrlRewriteModule;

            if (module == null || !UrlRewriteProvider.IsFurlEnabled)
            {
                // Break if the sender isn't a rewiter
                // or when friendly URLs is not turned on
                return;
            }

            UrlBuilder ub = new UrlBuilder(e.Url);
            // Remove /Mattias from the request
            e.UrlContext.InternalUrl.Path =
                Regex.Replace(ub.Path, "^/Mattias", "", RegexOptions.IgnoreCase);
            e.UrlContext.InternalUrl.QueryCollection = ub.QueryCollection;
            // Mark it modified, but not cancel the event
            e.IsModified = true;
        }
    }

    public class MyUrlRewriter
    {
        /// <summary>
        /// Handler to rewrite native Urls with query parameters to
        /// friendly urls
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EPiServer.Web.HtmlRewriteEventArgs"/>
        /// instance containing the event data.</param>
        public void RewritePipe_HtmlRewriteUrl(
            object sender,
            HtmlRewriteEventArgs e)
        {
            try
            {
                //Add "/Mattias" to the outgoing data.
                e.ValueBuilder.Insert(0, "/Mattias");
            }
            catch
            {
                // You should never catch all exception, but this is an example.
                // Important is that never throw an exception in the
                // friendly URL handling.
            }
        }
    }
}