Do you put ads in your shows? As a podcast coach, I suggest you have something to not only show how serious you are with a podcast, but also to give a break for you or your audience to catch up. I have documented before on getting sponsors, however, if you are not into monitizing your show, then how about a PSA (Public Service Announcement)?
NAB has a series of radio and video spots for your show which allow you promote a specific concern. From getting your GED, bullying, suicide prevention, to freedom of speech, Susan G. Komen foundation, March of Dimes, and more.
These are 30 or 60 second spots in audio or video format with bumpers in and out to place the ad.
To register and start using these spots, go to NABSpotcenter.org