In Magento we can create block with any content we need. For the first look Magento template system is unusual, because it consists of simple .xml files in wich is written where is situated file wich produce html output and where should be placed it's output. It's very easy. So let's begin. We need to create block with random products from current category and place it on products page.
First we need to create appropriate file in directory /app/design/frontend/your_current_theme/default/template/catalog/product/. Lets name it list_random.phtml.
Let's look on its content: