How do you get a true singleton in an ASP.NET app?

Something that has troubled me for awhile is that I can't quite figure out how to create a true singleton in an ASP.NET application. In other words, an object that lives in just once place, period. I thought that you could do this via an HttpModule, but when you debug you'll find that there is in fact more than one instance of the module.

I've also read that you can do it via global.asax in the Application_Start event, but that's less convenient because you can't configure it the same way you can an HttpModule by just commenting out the line in web.config.

I'm a little stumped.