Just found the first time I needed to filter rss. Now that would be a pit of work were it not for Yahoo Pipes. I wanted to get the podcast from NMA but they have Enhanced and MP3 in the same feed. I would not have bothered and just downloaded both each week but I gave Pipes a try and and less than a minute later i have a nice MP3 only RSS.
I also noticed that they have a new output option:
New Yahoo! Pipes PHP serialized output renderer
This could be really cool as I could do something that would be a few lines of code in PHP just with some drag and drop and a php call and I now have an array to play with.
I think I will have to find some use for this soon, as it seems so nice and easy.