Recent change notes
Released new version of Remote Groovy Console plugin. Now compatible with the latest IDEA 13 and IDEA 14. Also, IDEA hangup caused by race conditions during IDEA startup is now fixed.
General usage instructions
After installing plugin you will be able to create new type of run targets in your java projects - "Remote Console". This target will run Remote Console Server on port 7777, and after it you will be able to execute any script remotely in running application on-the-fly. Just select any text that contains valid Groovy script, and press Alt+Shift+Enter. If you want to use this plugin for your plugins developent, you can run Remote Cosole Server in IDEA JVM, using command from menu - Tools > Start Plugin Console Server.