A recent post from jQuery By Example has compiled an excellent list of plug-ins for jQuery Mobile. The plug-ins cover a wide range of functions, such as a Google Maps plug-in that allows the use of jQuery click events, rather than Google event listeners, and a fully-responsive, touch-supportive slider plug-in that can show slides containing all sorts of media. Each entry in the list is linked, but also includes a video or image to get a quick idea of what is or isn't interesting, and most of the plug-ins are free to download, though one is paid.
The plug-ins offer a number of simple solutions to help mobile sites and apps take advantage of the devices on which they're used, which can do a lot for user experience. After all, there's nothing worse than loading a mobile site and finding that it's just a clumsier version of the full site.
If you're interested in smoothing out your mobile site or app, check out the full list.