NPR Sunday Puzzle (Oct 16, 2011): Two-word Rhyming Phrases:
Q: Think of a familiar two-word rhyming phrase that starts with the letter F, like "fat cat." Change the F to a G and you'll get another familiar two-word rhyming phrase. What are these phrases?
My wife and I came up with the same answer and we need to get a hint up quickly, so I guess we'll go with that. I like the first as a familiar two-word rhyming phrase, but I'm not as excited about the second.
Update: After listening to the audio of the puzzle, I discovered that Will provided several other examples of two-word rhyming phrases (fun run, fine line, flower power) which would preclude them from being the answers. So you can scratch my original comment since it no longer fits and would have to change anyway.
Edit: My revised hints were "scratch" and "change".
A: Fender Bender --> Gender Bender