I've always loved clocks, especially ones with an unusual way of looking at time.

Here are some javascript clocks I've made:

Swatch® Internet Time A metric clock dividing the day into 1000 "beats", beginning at midnight in Swizerland (where Swatch's headquarters is), which is UTC+1. (Wikipedia article)
Metric Time My own take on Swatch time. Set in your local time zone, it's simply the day of the month with the decimal fraction included: Midnight on June 16th would be 16.00000, noon would be 16.50000 (half way to the next day) etc. With five decimal places, it divides the day into 100,000 units instead of our typical 86,400 seconds. Each unit is 0.864 of a second, one minute is 69.4 units.
Day Math Time expressed in various fractions of one day or the whole year.
Tiggr's O'Clock An old favorite of mine from a screensaver I used ages ago. A minimalist clock which is just an arc drawn from the hour hand to the minute hand of a standard clock face. Done here in HTML5. You can look at a sped up version that lets you get a feeling for how it looks at different times. Original concept by Pieter J. Schoenmakers
Tiggr's O'Clock (with lines) Slightly modified with marks for each minute, with darker marks for 5 minutes.
Doubled and zoomed Here, instead of an arc, the time is drawn as a pie, again from the hour hand to the minute. But the pie is drawn twice - one positioned so you're zoomed in on the minute hand, and one so you're zoomed in on the hour hand. It's really trippy when they meet. There's a sped up version of this one, too. :)
With color! Ooooh, pretty colors! (sped up version)
Hour hand Just an hour hand slowly making its way around the clock face twice a day, but zoomed in. Red lines are hour markers, green are half and quarter hours, purple marks 5 minutes, and blue one minute. (Sped up? Okay.)
Corners Four identical clocks, with red hour hands and green minute hands, but the clocks' centers are in the four corners, so you only see the "opposite" quadrant of each clock. Gray or blue minute markers appear near the minute hand, and purple hour markers appear near the hour hand. (Yep... there's a sped up version of this one, too.)
Circles 240 circles start the hour all lined up top to middle, in a line. Then, the top (red) circle goes around in a circle once an hour. The second circle goes around twice an hour. The 60th circle goes around once every minute (and is colored green). The circle closest to the middle goes around 240 times per hour, or once every 15 seconds. The cool thing is that any time you reach a fraction of an hour, the number of "legs" of the star-shaped monster will be the denominator of the fraction. At 1/2, it'll have two arms. At 1/3 it'll be three (every 20 minutes). At the quarter hour there are four legs, etc. There's also faster version with 1800 circles
Circles 600 circles start the hour all lined up across the top, in a line. Then, the top (red) circle falls once an hour. The second circle falls twice an hour. The 60th circle falls once every minute (and is colored green). The circle closest to the middle goes around 600 times per hour, or once every 6 seconds.

There's also slower version with 1440 circles: Red falls once a day, the 24th circle (green) falls once an hour, and the 1440th circle (white) falls once a minute.

Vernier This clock has a middle circle that rotates just like the hour hand on a normal clock, once every 12 hours. The outside of the circle is marked with 12 hour marks, subdivided into 6ths (further subdivided into 4ths). These subdivisions aren't to be read directly, however: they're part of a Vernier scale. The inside of the circle is also divided into 12ths, squeezed closer together by a ratio of 11/12ths. By looking to see which of the heavy lines is lined up, you can read off which 5-minute period of the hour it is. Look closer at the smaller marks and you can see exactly which quarter-minute it is!

There's also a version that's been zoomed in to where the minute marks line up on the vernier scale.