Theory: Average IQ as a function of group size
Warning: junk science ahead.
If you're an American, you probably already knew that yesterday (November 28 ) was Black Friday. If you're not an American, a quick explanation is that the day after American Thanksgiving is traditionally a day of massive sales in stores nationwide. This day inspires massive consumerism across the country, which results in an immense wave of items bought, money spent, profits made, Wal-Mart workers getting trampled to death...
Wait, what?
Yeah, you read that right. In a New York Wal-Mart, the shoppers simply could not wait for the doors to officially open, so they did what any rational human being would do: they bashed the doors off their hinges, pushed down the workers trying to keep them out, and trampled them beneath their feet as they went on their merry way looking for hot deals within the store. When they were informed that they had, in fact, just murdered one of the store workers and injured others, they reacted in an equally rational and tempered manner: they yelled that they had been in line since yesterday morning so they deserved to be shopping in the store.
Now, this is one of those moments where people stare at it, scratch their heads, and ask that timeless question asked so many times before: "How the #@^$ did this happen?" And most will never get an answer, instead simply shaking their heads and going on with their lives in confusion. But not I; I contend that I have solved this condundrum.
It's quite simple, really. First, we begin with the concept of decreasing marginal IQ contribution. While the old adage of "two heads are better than one" is quite clearly accurate, it is also quite clearly not the case that adding another person doubles the net IQ put towards the task at hand. This is due to ramp-up time, communication problems, and other such difficulties. Thus, if we consider an ever-increasing group of people of average intelligence, the marginal IQ contribution as a function of the number of people already working on the problem can be summarized thusly:
As can be seen here, it starts out quite strong, but quickly trends towards a net contribution of zero: adding another person will not increase the total sum IQ any further at that point. Thus, the effective IQ of the group of people can be summarized as follows:

However, this ideal case is not the situation realized in reality due to a second, competing concept which may be called IQ entropy. As human's IQ levels are inversely proportional to the size of their egos, anything causing an increase in the latter will inevitably lead to a decrease in the former. And what better ego-booster than being either in a group of people who are all like-minded individuals or in a group of people to whom one would never dare do something to lose face? Thus, the larger the group, the more IQ that is lost to IQ entropy, like so:
Thus, adding together the concepts of decreasing marginal IQ contribution and IQ entropy gives us the following final graph of average group member IQ as a function of group size:

Or, expressed pictorially:
1 Person

5 People

15 People

27+ People

Thus, on account of the fact that the group of Black Friday Wal-Mart shoppers numbered in the thousands, we can scientifically conclude that they were all long since clinically braindead, and should thusly be put out of their misery for their own sakes.
I eagerly await my Nobel Prize nomination, ladies and gentlemen.
Disclaimer: None of the above even remotely resembles sound science and should never be used for anything, ever.