An old site (2009), but I posted it because I just found it, and think that it's awesome that:

- You can move the pin around and see the sun's angle and path change in real-time

- You can slide the time bar at the top to watch the sun's path move

- You can adjust the date at the top to watch the duration of daylight shrink and grow

I started working out of a home office this year for the first time, and the sun has been poking in one of my windows later in the day. So I used this, out of curiosity, to figure out when (in the year) it will start doing this later in the day (after I've quit for the day).