I have a winforms project based on the 2nd winforms sample (content loading).  I don't want to dynamically run the content importer at run time - at least for most things - like my .fx files - I'd rather have it put at compile time into the .xnb file (I think?) like a normal game.

What's the best way to go about doing that given that my project doesn't really know about content like a regular xna game project does?  Is there a way to "add that functionality" (e.g. the Content folder) to my project?

The easiest way is to add a "Windows Game Library" project to your solution. This contains a Content project that you can use to import and compile your assets. Set the project's output folder to the same as your Winforms project.

Note: This will create a dll and pcb file for the project which you can just delete after build.

Thanks!

I ended up making a new library project, and putting the content in there - and then the winforms project uses that library. 

And somehow the library's content files are being copied to the output directory of the winforms project when I build - not sure how/why that's happening, but it's good.

First, you must build the content alongside your project. This is done by adding an XNA Framework content project to your solution. There is no direct way to create a content project. You can make one by creating a temporary "Windows Game" project, then copy the resulting .contentproj file into the same directory as your WinForms application and add it to the solution. The .contentproj extension is not recognized by the Add Existing Project dialog box, so you must type in the entire project file name (including extension). You can now add content files, such as the Arial.spritefont used in the sample, to this content project. To ensure the content project will always be built before you run the program, right-click the main project, choose Project Dependencies, and check the content project. To make sure the output content files are placed in the right directory, open the properties for the content project, and set its Build / Output path property to the correct location (make sure you do this for both the Debug and Release project configurations).