With Halloween around the corner, to get in the mood, you might want to check out this Jack-o-lantern Halloween screensaver for Windows 7. “Watch as different faces are carved into jack-o-lanterns.”
This screensaver is spyware free and you can download it from AmericanGreetings.com for free, although you will be asked to submit your email id.
You might also want to check out some more Halloween screensavers for Windows, here and here.
Screensavers are a vector for spyware and adware and one must therefore be very careful while downloading and installing them.
These Halloween themes for Windows 7 may also interest you!