This was an event related to Futurama.
I looked on the list of questions ordered by date and noticed a lot of Futurama questions on 28 June 2012. Personally I wasn't around at that time, but I've heard about this event from DVK, who said:
sigh. I was SOOOO hoping that the Trauma of Futurama was fully behind us :( Basically, we got overflooded with Futurama questions, many of questionable quality, as part of a promotional event.
-- DVK, 7 Dec 2015
For more details, have a look at the various meta posts thrown up by this search. Notice the date stamps: they're all in June or July 2012. In particular, here are two posts from 28 June. Congratulations on being mentioned on Futurama's Facebook page! says:
I was browsing Facebook this evening and noticed a link to the SciFi Stack Exchange on Futurama's newsfeed! Congratulations - this should bring a good bit of traffic.
And then the results of this promotion. Holy monkeys Batman! That is A LOT of posts! says:
I think due to what happened here: Congratulations on being mentioned on Futurama's Facebook page!, or most probably here: https://www.facebook.com/Futurama/posts/320014191418612
We are getting MANY futurama posts within the past few minutes.