Just do a mk and run the resulting binary. Rio works as normal, except that mid-clicking outside of any window brings up a menu with the different virtual desktops listed. To my knowledge, this works just like p9p rio's virtual desktops. The new options: '-n' will enable "nostalgia mode", which for now emulates the 8½ window border color and style. '-b 0xrrggbbFF' will set the background color to rrggbb. The trailing 'FF' does not appear to be important. The default color is 0x777777FF.