If you like to switch out your screensaver to match your mood or the time of year, Boo Screen Saver might be a good choice around Halloween, especially if you have kids. The only downside is a relatively high price tag for a screensaver that you'll only use for a few weeks each year.
There's little the user has to do to once Boo Screen Saver has been installed. The cartoon-like graphics have all the typical Halloween fare, from a ghost to a witch on a broom, but the "scare factor" is very low. This isn't Freddy Kreuger; it's Linus in the pumpkin patch. There are some sound effects, which could startle you when the screensaver kicks in, but again, they're PG and not R-rated, and you can easily turn the sounds off. There's not much more to this basic app, which you can try out for 30 days. After that you'll have to ante up $6 to keep the basic screensaver. Overall, the graphics are good, but not great and the sound effects will probably only last a few sessions before the user opts to turn them off.
There's nothing truly special about Boo Screen Saver, but it works as promised. If you're a big fan of Halloween and just have to bring the holiday to your computer, the 30-day trial is more than enough time to see if this themed screensaver is worth paying for.