Tickets for the Celebration Europe II are supposed to go on sale tomorrow (http://www.starwarscelebration.eu/). This will clearly be one of the most interesting and engaging fan events this year. This is probably also a good oportunity to let everyone know that we are currently looking into the option to move this years Dev Meeting to Essen (and thus give everyone the oition to meet our developers at the convention). We originally favoured Atlanta and Dragon*Con, but after Celebration Europe II has been announced, we see this as a very interesting option. Nothing has been decided yet, so if the opportunity to meet the Combine developers at the convention would be the only reason for you to buy tickets for the convention (and we would be much flattered, if it were), please wait until we can confirm dates and place for this year's Dev Meeting.
Edit: Update on the date. Sales will start "at 6 PM in Germany, 12 PM in New York, and 9 AM in San Francisco on January 17".