The icons include a spider for My Documents, and a skull and cross-bones for the Recycle Bin. Your pointer is a kernel of candy corn for a pointer that turns into a glowing Jack-o-Lantern when the computer is working, and you get an unobtrusive gold I-beam in open apps.
The sounds are sparing, but appropriate: Make a mistake and you get a ghoulish howl. Windows and menus get a complete makeover with gothic-looking fonts and orange title bars.
Installation: Unzip the files and copy them into Program Files/Plus!/Themes. To get the fonts to work, however, you'll need to open the Halloween folder within Themes and copy them to WINDOWS/Fonts.