private void LogInUser()
        {
            if (!User.Identity.IsAuthenticated)
            {
                FacebookWebClient fb     = new FacebookWebClient();
                dynamic           result = fb.Get("me");
                long fbId = long.Parse(result.id);

                AppUser appUser = Ctx.AppUsers.FirstOrDefault(u => u.FacebookId == fbId);

                if (appUser == null)
                {
                    appUser = AppUser.CreateAppUser(fbId);
                    Ctx.AppUsers.AddObject(appUser);
                }
                else
                {
                    if (appUser.LastVisited != DateTime.Today)
                    {
                        appUser.LastVisited         = DateTime.Today;
                        appUser.InvitationSentToday = 0;
                    }
                }

                Ctx.SaveChanges();

                FormsService.SignIn(appUser.Id.ToString(), false);
            }
        }