JUNE is a four-letter word, but Shez said he/she was coming for four months (unspecified which months and has not replied to request to be more specific)), so not unreasonable to mention other good festivals any time between March and September - 4 months before and after, but including JUNE! I kept my list to those that I know do have a large proportion of UNACCOMPANIED singing!! (Which was also requested).
Or did you have some other 4-letter word in mind, Steve?