Some more ideas for happy hour:
It would be nice to have total number of clintz collected per happy hour as message after HH is over.
AND of course have "Party all night" type of missions related to happy hour. (Collect 500 clintz and 5000 clintz from happy hours, knock out 50 opponents during happy hours etc)..
Happy hour is not that friendly to people in other time zones. I recommend the next time this event is run is that the hours move by an hour for 24 straight days, that way everybody would be able to play this event.
And please change how you say the time. I don't think that anybody uses the time description of GMT +1:00. Instead you can say Central European Time, or just say Paris (Amsterdam, Berlin, Rome, Madrid, Stockholm, Vienna, Barcelona, or any large European city in that time zone) time. Most of us have smart phone where we can see the time by city, but not by GMT +1:00. If you plan on using GMT, then just say GMT.