I do recall the "how to host/do forum events" threads and guides in ES HQ we made being relatively well put together - perhaps you could expand on those, if you haven't already, into the realm of quick to prepare "instant" events - simple stuff that a willing member of the team could do almost on the spot, by changing some variables in the thread and posting it as is, with less jaw-dropping prizes and short deadlines (f.ex. up to 5 days). That would create a certain dynamic in the events board, changing it's sorry state in between the big events.

Another thing I conceptualized but didn't get to introduce and implement when I was still in the team, was a think-tank for the creation of forum events. Such group would consist of ex-staffers and active memebers of the community, interested in helping out. Certain level of discretion would be recquired, not to spoil the contents of the discussed events too soon, however without any mind-blowing recquirements to actually join the group, with the exception of the memeber limit at given time - up to 10 people. The group would operate in a special board, but without access to any staff boards, as it isn't needed and would only make a possibility of some leaks more likely. Their aim would be to create and prepare [PROP]s of interesting events, that a member of ES could take and host without having to conceptualize it him/herself - taking some load off the ES (some people, while good at in-game hosting, can't for the love of them sit down for 30-40 minutes and write down an ok-ish event [PROP]).
Inactive people would be removed quickly, making place for the new ones. Such "database" of possible events would come in handy in situation such as the current one.
Staff would obviously oversee the group, giving CnC, giving ideas, sometimes letting the group know in what direction to look, as events of this or that theme might be happening in the future, but for the most part they would simply do their "job" by coming up with "hosting-worthy" and "hosting-ready" events, widening the hosting possibilites for the ES. Of course, if an event created by the member of the group was used, all the people that worked on it would get their due credit in the event thread.