Options
DaylightMap.com
DaylightMap shows the pattern of night and day on a Google map, for any area of the Earth, for any date and time. The night-side satellite view includes city lights as seen from orbit.
It also allows you to select up to ten locations on the map; in addition to seeing at a glance whether it's daytime there, you can show their local time, sunrise and and sunset times, and length of day. These locations can be remembered for future visits, saved as a bookmark, or sent to other people as a web link. This site can thus function as a graphical world clock, and can be used to show relative times of any future or past event.
This particular DaylightMap is highlighting times for .
Mobile phones running the Android operating system - the Droid, Galaxy S, Nexus, and more - can now have DaylightMap on board. The app is called TerraTime, and it also offers the daylight map plus globe, as well as a portable version of my DaylightClock. Give it a try!
There's also a near-real-time view of global cloud cover available, updated every hour from weather satellite imagery. It's interesting both for looking at the big-picture patterns, as well as a more localized picture of what the weather is doing in your part of the world. A specialized cloud-cover view is available as well, my Hurricane Watcher.
More recently, I've packaged the DaylightMap + Clouds functionality as an iGoogle Theme, meaning you can now wrap your whole Google home page in a DaylightMap.
Or, in the best mashup tradition, you can put DaylightMap and Clouds on your own website if you'd like. It's available as a gadget which can be placed on iGoogle, blogs, or practically any other site.