I.) Jointly with Frits Beukers and Jan-Hendrik Evertse I organized the 60th birthday workshop for Robert Tijdeman, July 28-August 2, 2003, Lorentz Center, Leiden, Netherlands. There are no conference proceedings of this conference.
II.) Jointly with Sergiy Kolyada, Mikhail Kapranov, Yuri Manin and Leonid Potyagailo I organized a conference in memory of Alexander Reznikov which was held Sept. 22-29, 2006 in Bonn. There will be conference proceedings that will be published by Birkhauser (planned publication date: December 2007).
III.) In February 2007 a two day lectures series on classical and modular approaches to in Diophantine equations will take place. I organized this together with Prof. A. Dabrowski.