There is a very wide choice of different modal window effects available. The easiest way to set one up is to use the Lightbox, Fancybox or Fancyzoom effects supplied with Pluskit (not included with this theme). Alternatively you can add you own to the theme. Generally adding any type of modal window effect requires the use of custom code and some editing to the theme may be required. There is a huge choice of modal effects available under a range of different licenses. Ones powered by jQuery tend to be easiest to setup, but MooTool powered ones such as MediaBox Advanced give more dramatic effects.

A number of third party tutorials have been produced on adding modal effects to projects. It would be worth searching the RapidWeaver forums for more information or searching the internet for details. Each effect requires a different set of instructions to follow.