Run own auction site like ebay with this PHP script. Members run paid or free auctions. Also supports Dutch auctions, classifieds, fixed priced items. Demo available.
A content management system provides great way for starting own jokes site. Advertising opportunities include banner ads, google adwords, affiliate ads. [Commercial]
Act as a collection of private and public image galleries. Members or administrator can create public or private galleries. Public galleries are accessible to all. While read/write access for the private galleries can be restricted. [Commercial]
Link validator tool written in PHP helps to check automatically if a page contain a link back to site. Helpful especially in link exchange or link popularity campaigns.