I’m a big fan of the National Park Service’s webcams, especially the Washington DC cam viewing the Mall area from the Netherlands Carillon on the GW Parkway. Having a windowless inside office I like to keep this cam (among other outdoor DC cams) open in a separate browser window to provide an outside view through the course of the work day. I’ve also used it for at least one time lapse video.
Checking the cam tonight brought an especially cool treat: a long exposure shot catching a plane making the River Visual approach to landing at National:
Update: Oh nice, check out brianmka’s incidental capture of a landing plane at night from right near the same webcam.