How can I create custom context menus in Windows?

[HaRuMaN]

More specifically, I want to right-click on a folder and have a command available, like Play Folder.

Basically, the command would need to be something like:

C:\program.exe C:\folder_that_I_just_right_clicked -extraswitches

Stuff in red would change depending on the folder right-clicked upon, while the text in blue would remain constant.

Thanks! 

[ChadTower]

Registry entries.  Do some googling on "windows context menus" and "registry".