Obligatory warning: This script has been designated as an obsoleted "Retro Script". There is no guarantee that it will function as described with modern versions of iTunes and OS X. If used in its current form it may not work at all without modification and, at worst, it may corrupt or destroy data.
iTunes will stop updating a podcast if you have not listened to at least one of its episodes in five days. This script will batch-update every podcast subscription so you don't have to manually update each one individually.
I have posted instructions on how to create a launchd agent to run this script automatically and invisibly in the background to ensure that your Podcasts are always updated.
Possible iTunes bug (July 17, 2014): Looks like the iTunes AppleScript command updatePodcast command is broken as of iTunes 11.
downloaded 8m 44s ago
Apply selected CD's CD Text to its disc and track tags
downloaded 24m 44s ago
Display, create text file listing info of dead tracks
downloaded 31m 32s ago
Export album artwork as folder.jpg to Album folder
downloaded 33m 59s ago
Export artwork of selected tracks to parent or specified folder
downloaded 35m 12s ago
Restore each selected track's artwork from an image file stored in its Album folder
downloaded 38m 18s ago
Exports and then re-imports selected tracks' artwork