I need to let end users specify a time range, to be stored and used internally as a starting date/time and ending date/time. The range could be minutes or it could be days.
This comes in late, and it's not a control per se. I read this idea on a blog I can't find anymore (in fact, I found this post while trying to find it). The idea is to use the metaphor of a wall clock. Here's what I implemented for the fun of it. It's not a functional control. You could use something like this as a starting point for capturing times naturally. Three clicks at most, two most of the time. Only dials come close.
http://www.viridium.ro/clock-sample/
Use a HTML5-aware browser; that is, Chrome.