Groovy Tools

Groovy Monkey
http://groovy.codehaus.org/Groovy+Monkey
IntelliJ IDEA Plugin for Groovy
http://groovy.codehaus.org/IntelliJ+IDEA+Plugin
Eclipse+GroovyConsole
http://groovy.codehaus.org/Eclipse+GroovyConsole

More stuff

http://groovy.codehaus.org/IDE+Support