C. 1,500 (a little under if memory serves)
One thing I would like to say on behalf of the MT, and this is regardless of whatever event(s) are arranged by the Hub Captains and us in the Online Dept: I'd really like to establish a EuroHarmony "Crowded Skies" record/benchmark (and when the time comes, a similar record/benchmark for VATSIM) that we can then look at beating in the future.
So, at around 2100Z on Saturday, lets see how many 'Harmony callsigns we can have in the air on IVAO, eh? (And Brian, if you want to do your 1st session any time in the evening between now and Saturday, and that's all day Saturday; up to 1900Z, let me know ASAP...)