For a while (maybe since the beginning of the summer) podcasts downloaded via my iTunes feed have often been corrupted.

They may skip to the end unexpectedly. 

Skip Skip

They make weird squeaky noises. 

Get out of my feed, Squeaky.

Sometimes you hear an anomalous few seconds of another podcast.

You....don't...belong....here!

 I sent a query to Apple about it but, of course, I got no response.

He's dead, Jim.

 I just updated to iTunes 11.1.0.126 today and it didn't help.

So I got an idea while looking at the podcast download window.

Several podcasts were downloading at the same time. I wondered if Apple was using some kind of  glitchy accelerator to speed up and maybe screw up the downloads. 
Then I noticed the "allow simultaneous downloads" box and I unchecked it figuring that iTunes was crossing the streams. And anyone who has seen Ghostbusters knows that one should never ever cross the streams. 

Egon Spengler: There's something very important I forgot to tell you.

Peter Venkman: What?

Spengler: Don't cross the streams.

Venkman: Why?

Spengler: It would be bad.

Venkman: I'm fuzzy on the whole good/bad thing. What do you mean, "bad"?

Spengler: Try to imagine all life as you know it stopping instantaneously and every molecule in your body exploding at the speed of light.

Ray Stantz: Total protonic reversal.

Venkman: Right. That's bad. Okay. All right. Important safety tip. Thanks, Egon.

Voila! 

After listening to a couple of newly downloaded podcasts I have experienced no problems. 

So if iTunes is giving you agita when you listen to podcasts, uncheck that box and let them download one at a time.