I'm aware of background tasks, but they don't run in the same way as the application. There are limited things you can do in the background and if your app has background tasks, it will still show suspended in task manager when it isn't visible. It will also get very small slices of the CPU.

>This article suggests that is not always true:
>http://news.softpedia.com/news/Windows-8-Metro-Apps-Can-Run-Even-If-Suspended-Tanks-to-Background-Tasks-224665.shtml