If you use that much Red Bull, you got 2 issues (at least): the sugar gives a rush, but the bloodsugar level will plunge. And each time you continue it plunges even harder and faster.
Second, Red Bull or any caffinated beverage will attack your adrenal gland badly. Realy hard. Your adrenal gland is responsible for your adrenaline (duh) and gets triggered by the caffeine. So, it's not the caffeine that gives you a boost, but the adrenaline that gets released. Until it's gone, drought up, vanished. You can drink Red Bull till you die, but the adrenaline won't be there. Until you fix it.
You see, your body is a bank. A bank full of nutrient to be released when some other part of the body needs it. If you never make deposits, you won't get any interest either. If you only make withdrawals, you will end up with debit. If you continue you go bankrupt and die.
Healthy hackathons? I guess it's possible. I eat a lot of butter from grass-fed cows. I use omega-3 a lot and magnesium. My brains work much better and that without any caffeine. There are other supplements one can use, but always with moderation and enough sleep. Without sleep, your hormones won't get any rest or balance.
Hackers who think they have super powers and don't need sleep are having a Wall-Street mentality prior to 2008. Grow up, you only have one body, so you better take care of it.
mod_limitipconn doesn't work, because there is no completed request for a connection. There was a handshake and part of the request is sent, but does Apache see that as a connection? I think not.
Apache (and any other server) should expect a full request within a time frame. A headerset should not take long to load over a normal network. If the header is not completed after a while, disconnect the request. This also helps for requests that have not been setup for a DOS too.
I'm not an expert, but for me, I would look in to the headercompletion part and not into limiting connections or whatever. If I would have the knowledge, I would try to hack it in the Apache sourcecode, but I can't.
If the journey is more important than the destination, knowing shortcuts doesn't bring you any experiences. You would want to prolong the journey more and more and avoid shortcuts altogether. I wouldn't listen to the anecdotes of a known 'adventurer' who only took shortcuts. I like to listen to somebody who has been there, done that and bought the t-shirt, not to someone who only bought the t-shirt.
Likewise, if your 'friends' from school enter the same job market and get the job you could have instead, you pitty them for cheating and even helping them. You know what you're worth and can withstand the tasks they throw at you. While cheaters don't know and don't understand the world they operate in. They probably keep on cheating....
Actually anything natural, organic food is stimulating the body, while anything artificial, fabricated food is destroying the body.
So if you want to hack along with a sharp mind, keep your mind in shape by replenishing the body with what it needs. Period.