Italy: Venice‘s Historical Regatta.
England: London, Chelsea Antiques Fair mid Sept.
Ireland: Galway International Oyster Festival, (including song and dance, of course! )4 days, late Sept.
Wales: Festival of Music and Arts, Swansea (theater/music/opera/dance) 3 weeks, Sept-Nov.
Germany: Berlin Festival (music of all sorts, drama, art) early Sept-mid-October.
Munich’s Oktoberfest beer frenzy starts mid Sept – early October.
Czech Rep., Prague, Autumn Festival – orchestral concerts and opera.
Greece: Athens Festival, drama and music in ancient theatres. June-Sept.
Denmark: Arhus Festival (including a Viking Festival), varied music and drama performances, 9 days beginning the first Saturday in September.
France: Chaumont Garden Festival – thirty wonderful and sometimes wacky show gardens around a perfect chateau (castle), every year 15 May-19 October.
Also see European Festivals or Arts Festivals for suggestions, information and dates.