Earth and Sun is a neat interactive tutorial on what makes a day for people on Earth. In specific, it explains the Earth's rotation, revolution, speed, axial tilt, solstices and equinoxes, and more that you haven't thought all that much about.
The duration between two solar noons is known as a solar day which lasts the familiar 24 hours. However, that’s not completely accurate. If you look closely at the simulation of the sidereal and solar day you’ll notice that we didn’t account for two important factors – eccentricity of the orbit and the axial tilt of the Earth. In fact, 24 hours is the duration of a mean solar day. The actual duration of each individual day varies, but before we witness that variation we have to discuss the most important consequence of the axial tilt.
In the visual shown here, you can drag the Earth around on any axis, but you can't change where the sun is, so depending on what time you do it, you'll see where daylight and dark falls. That's just one of the many ways you can visualize what's happening on Earth at the site. -via Metafilter