Time.
Get the time from the US Naval Observatory Master Clock.

World Clock.
Uses data from WHO, UN, Internet World Stats, and other official sources to produce a series of real-time clocks counting not only population but also things such as number of bicycles built, number of barrels of oil pumped, earth temperature, number of internet users, and more.

World Clock - Time Zones.
Find the current local time anywhere in the world. Click a location and get the current weather, a 48 hour forecast, the phase of the moon, and more.

World Population Counter.
Estimated world population; updated every 30 seconds. Also has links to the US Bureau of Census World POPClock and National POPClock.