You can use the Content Query web part within a SharePoint site without activating publishing feature (which you may want to do as activating the feature introduces and changes a lot of options):
- Go to the Web Part Gallery within an existing publishing site
- Export the ContentQuery.webpart file and upload it to the Web Part Gallery of the destination site
- Copy the three .XSLÂ documents (Header, ItemStyle, ContentQueryMain) from the XSL Style Sheets folder within the Style Library and transfer them to the destination site