Beermathics or "An infinite number of mathematicians...

...walk into a bar.
The first one orders a beer.
The second orders half a beer.
The third, a quarter of a beer.

The bartender says "You're all idiots", and pours two beers."

Now, allow me to be the brilliant mind who will do the math for his moronic readers unfunny/killjoy guy who will explain the joke here:

Let's label the mathematicians with 'n', with n going from 1 (the first guy) to ∞ (the "last" one):



We should also label the amount of beer that each one drinks as beer_n Then we'll have this:


...

From this we can derive the general formula that gives us beer_n, i.e. the amount of beer that the n-th mathematician will drink:





So, all the clever barman had to do was to add all the terms in the series which, predictably gives out...




It just goes to show that brilliant minds nerds can have humour inside jokes that no-one cares about, too.

[via Talk Like a Physicist, who found it here, who in turn found it here, and so on ad nauseum infinitum]

(later addition: The title is -[sarcasm]obviously[/sarcasm]- a quasi-reference to this)