Complex sentence: Grimwood was guest of honour at Novacon in 2003, at Kontext (in Uppsala, Sweden) in 2008, and at Eastercon LX (the 60th British National Science Fiction Convention) in 2009.
Split into simpler sentences: Grimwood was guest of honour at Novacon in 2003, and at Kontext (in Uppsala, Sweden) in 2008. He is scheduled to appear at at Eastercon LX, the 60th British National Science Fiction Convention, in 2009.