maven-archetype-plugin is an archetype which generates a sample Maven plugin:
project |-- pom.xml `-- src |-- main | `-- java | `-- $package | `-- MyMojo.java |-- test | |-- java | | `-- $package | │ `-- MyMojoTest.java | `-- resources | `-- project-to-test | `-- pom.xml `-- it |-- simple-it | |-- pom.xml | `-- verify.groovy `-- settings.xml