R package: Where to put code to Run Once Only?

Is there a specific place where we can place code to run once only in a
package?

I have code that switches based on Sys.info()[["nodename"]] - but since this
just about never changes, I would like to run it only once when someone
runs:

require( mypackage ) or library( vte )

I'm tempted to have some free-floating code in global space (in one of my
package's .R files), but it just seems so wrong/hacky to do it this way.

Where is the proper place to put this code?

- Ken