OWAPS's WebGoat is an application that is built to be vulnerable to attack, it is a simulation of real world vulnerabilities. The Whitebox is a collection of real world vulnerabilities, it has 2 web applications that where abandoned because the applications where so insecure. It also has a set of challenges there are vulnerable code snips taken from real world applications. This project has real world sql injection as well more serious vulnerabilities.
Try scanning the vulnerable apps with Wapiti (open source) or Acunetix ($) or NTOSpider($$$). Then try using the applications, create blog posts ect, and then scan it again.
Also check out Damn Vulnerable Linux and Google Jarlsburg.