The Electronic Frontier Foundation has released Switzerland, an open source software tool for testing your ISP's net neutrality.
Here's an excerpt from the announcement:
Part of EFF's "Test your ISP" project, Switzerland is an open source, command-line software tool designed to detect the modification or injection of packets of data by ISPs. Switzerland detects changes made by software tools believed to be in use by ISPs such as Sandvine and AudibleMagic, advertising systems like FairEagle, and various censorship systems. Although currently intended for use by technically sophisticated Internet users, development plans aim to make the tool increasingly easy to use.