On Friday, there is a Drupal meetup happening in Utrecht, The Netherlands. I'm planning to attend so looking forward to meet some of you there.
On Saturday and Sunday, a smaller group of core developers will meet in the offices of One Shoe in downtown Utrecht to work on the ongoing Drupal 7 usability efforts. According to the event page on groups.drupal.org, confirmed attendees for the sprint include Leisa Reichelt, Mark Boulton, Gábor Hojtsy (goba), Damien Tournoud (DamZ), Erik Stielstra (sutharsan), Bojhan Somers (bojhan), Roy Scholten (yoroy), Bart Feenstra (Xano), Gaele Strootman (gaele), Kristjan Jansen (kika), Thomas Moseler (eigentor), Konstantin Kaefer (kkaefer), Philip Vergunst (skilip), Willem Mol (Whatdoesitwant), Berend de Boer (berend), Maarten Verbaarschot (mverbaar), Johannes Haseitl (derhasi), Steve De Jonghe (seutje), Clemens Tolboom (clemens.tolboom), Thijs Zoon, and Floris Derksen. I plan to stop by on Sunday as well.
Though the open sign-up for the code sprint on Saturday and Sunday has already closed due to the number of attendees already confirmed, contact Thomas Moseler (eigentor) if you want to attend and he may be able to squeeze you in. He's also actively looking for sponsors to help some European core developers to attend the Utrecht activities; if you can help, please send him an e-mail. Thanks!