The late composer Jonathan Harvey, who died last month at age 73, described his Speakings (2008) as the most complicated and ambitious work he had ever written. A 25-minute composition for orchestra and electronics, the piece certainly warrants that description on the levels of scale and logistics alone.
Conlon Nancarrow may be most famous for his player piano studies, all of which were performed at the Southbank Centre last weekend, but his instrumental music is worth a listen too. His Third String Quartet is perhaps his most important effort for 'actual' performers rather than machines, but on Sunday night the Arditti Quartet also made a decent case for the First Quartet.