I listen to podcasts of varying lengths. Many try to fit pretty close to an hour, but I prefer ones that let the episode breathe, running as long as they need to, whether that is 90 minutes, 120 minutes, 180 minutes, or even longer.
But I also appreciate the shorter podcasts, and wrote about some of my faves in a prior entry. To that original list, I would add a few more:
Fantastic Fourcast -- Dave Elliot releases 2 to 3 episodes per week, running 10-12 minutes each. Each episode covers a single issue of the classic Marvel comics title, The Fantastic Four.
The 20-minute Longbox -- As the name implies, this show is designed to be 20 minutes, and host Steve Lacey does a pretty good job at bringing his shows in around that time. This is also a comic book podcast (sorry, I listen to a TON of comic book podcasts), the unique aspect being that Lacey uses a random number generator to determine what specific issues he covers.
The Malex Minute -- Although this show stopped producing new episodes at the end of 2012, the shows are still up, and I highly recommend them. It is a hilarious show that chronicles the life and times of a fuzzy alien creature, a talkative laptop, and the poor human they live with.