1. Infinite mathematicians walk into a bar. The first one orders one beer. The second one orders half a beer. Before the third can place his order, the bartender slams two beers on the counter and asks the group to move on

2. Infinite mathematicians walk into a bar. The first one orders one beer. The second one orders half a beer. This time, the third one gets his order in before the bartender can react: he orders one-third of a beer. The bar stays open forever