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 24s ago
Export album artwork as folder.jpg to Album folder
downloaded 1m 40s ago
Delete characters from the beginning or ending of selected tracks' name, artist, album, comments, composer, or show tags
downloaded 35m 3s ago
Gather audio tracks whose files contain no artwork metadata
downloaded 35m 34s ago
Add or subtract a user-entered number from each selected track's Plays
downloaded 36m 18s ago
Rename selected tracks' Song Names with their filenames (minus extension)
downloaded 45m 34s ago
Exports and then re-imports selected tracks' artwork