Windows 8 'store' apps (the only kind supported on Windows RT) are meant to be installed via the Windows marketplace, but there are situations in which it would be useful to bypass this. For example, during beta testing, a developer might want to release an application to a limited audience before making it available in the store. Or maybe my friend writes something, and I'd like to load it onto my Surface?
How can I do this? Is there a mechanism where I can decide to install an application supplied directly by a developer?