Active=iPercentGamesActive this value determines the probability that this event is included in the list of Events possible at the start of a new game
Weight=iWeight this value determines the chance for the event to trigger IF any event is triggered (I listed the chances per era in my first post) AND IF its Prereqs are met - what the game does is:
1 - it determines whether any event is triggered this turn
2 - it lists all events that are active AND have all prereqs met AND are not obsolete
3 - it adds all iWeight values of these events
4- it rolls the dice, with the chance of any event to occur being iWeight/Sum(iWeight) from 3