Adapted from an email I just wrote Kit, who wanted cool physics videos for a high school math class. These will be familiar to many -- from the feed -- but aren't archived anywhere, so it is perhaps worth collecting the links here.
1. Stephen Morris's fluid-mechanical sewing machine (maple syrup -- not really, but he is Canadian -- dropped onto a moving belt):
2. Stephen Morris, "chemical plumes" (Quicktime) and the "washboard road" effect (i.e., the fact that dirt roads go sinusoidal over time when driven on). Should note in passing that talking to David Grier about washboard road was one of the things that sold me on many-body physics as a prospective graduate student.
3. Sid Nagel's splashing-droplet videos (scroll down). The discovery that water doesn't splash at low atmospheric pressure is remarkable and not something I'd ever have expected. The other stuff on Nagel's website is pretty neat as well. (Either Nagel or someone introducing him described his lab as "where theory comes to die.")
4. The phenomenon of self-propelled Leidenfrost droplets moving uphill (U. of Oregon; see my recent post for context; this youtube video is a decent intro to the Leidenfrost effect).