For me, there are two types of hackdays... Competitive and Cooperative - CharityHack for instance - Big prize, big turnout and big competition, some people (myself included) go to win, we've been accused of cheating at that event and it puts a sour taste on it. Competitive hackdays are different as theres less talking, less fun, a lot more stress and more of a purpose to get the hack finished and presentable,I also find them to be a lot more based on the end presentation, the amount of hackdays I've seen where the people could have built nothing but produced a pretty slide deck is astounding and sort of feels like a wasted weekend to me, We work hard on our presentations but we make sure they at least demo what we've built! Cooperative hackdays are much more fun, they are there for you to try something new, work with different people and learn something, anyone who has been to LeedsHack knows that there isn't really a massive prize for the weekend (We might have a Nexus 7 or two) but everyone who enters gets a poundshop prize and everyone leaves with a good feeling, our next hackday (http://pibakeoff.leedshack.com) is much of the same, less about the prizes and more about people just getting today and playing with a cool bit of technology. I don't mind there being two types of hackday, I enjoy them both.. but maybe the competitive hackday needs to be called something different? In regards to people cheating, We always make sure to have at least two technical judges on hand to look at if things are actually possible in the 24 hours and to do some simple checks to check for pre work, it doesn't always work but it cuts down on the blatant (we added this feature so are submitting the whole app as a hack)