I'VE GOT A HEADACHE

Via Mark Kleiman, (who found it via Volokh) check out these lesser-known conversion tables. A few examples:

Ratio of an igloo's circumference to its diameter: Eskimo Pi

Speed of a tortoise breaking the sound barrier: Mach Turtle

365.25 days of drinking low-calorie beer because it's less filling: 1 lite year

***GROAN***

But please, read the rest, there's much more.