Event blogging is a new trending topic and I have seen many people trying it out but the efforts involved in setting up a blog for trending events (unique events rarely talked about not the ones you mentioned which already has great competition in SERPS) is too much compared to that $300 or $400 gain from it on weekly or monthly basis. It takes weeks to rank for keywords based on your local traffic but it will take seconds for all that traffic to disappear the moment the event ends.
One permanent blog which can drive you a consistent flow of income is better than thousands of event blogs that involves higher stress but smaller ROI (return on investment)
Most Event bloggers often lose their adSense accounts or are banned for spamming the web.
I personally consider Event blogging as Spam because they have poor quality and out-dated content with no consistent posting frequency. It was easier to rank for such Fly-by-night blogs 3 years back but Now Search engines are quite smarter and they can differentiate a "A New Spammy Stranger" the moment they index it.
I tried my best to be honest in this case