Getting the List of All running active HttpModules.

//Get Application Instance from Current Content
HttpApplication http_apps = HttpContext.Current.ApplicationInstance;

//Get List of modules in module collections
HttpModuleCollection http_module_collections = http_apps.Modules;
Response.Write("Active HttpModule Count : " + http_module_collections.Count.ToString() + "</br>");
Response.Write("<b>List of Active Modules</b>" + "</br>");

foreach (string active_module in http_module_collections.AllKeys)
{
    Response.Write(active_module + "</br>");
}