Where to store variables for entire application

My theoretical Flex Viewer application has need for keeping track of various data across the whole application, rather than local to a widget or two. Multiple widgets will often want to read/write to some global variables.

For example, if I log in as user#381 and select project#4, I want all widgets to be able to see at any time what user is logged in and what project was selected.

What's the best way to do this? I thought about AppEvents to communicate between widgets, but this is more about variable storage, not communication. I don't want every widget to have to keep track of what user is logged in or what project they are accessing.

Thanks!