Selenium downloads: http://seleniumhq.org/download/
Selenium with Java: http://seleniumhq.org/docs/appendix_installing_java_driver_client.html
Groovy: http://groovy.codehaus.org/Tutorial+1+-+Getting+started
Extract selenium-remote-control
Copy selenium-server.jar and selenium-java-client-driver.jar into groovy/lib
Start Selenium server: java -jar selenium-server.jar
Start groovyconsole
Open selenium script
Run with Ctrl+R