How about a way to rip those "plays only on a CD player, not on a computer" CDs?
Depends on the copy protection format used, there are several different ones. The various copy protection formats are discussed at
www.cdrfaq.org if you're interested.
I, personally, have seen only one copy-protected CD, and the rip method is pretty straightforward.
They had tagged all the tracks as data tracks instead of audio tracks. They really were audio tracks, they just had the bit set that told the index they were data tracks. This makes most rippers just skip them and not bother ripping them, while many (not all) consumer CD players will dutifully try to play the tracks.
The solution is to rip the disc using one of the programs that will rip it in "Raw" mode, then edit the resulting cue sheet so that the tracks are audio tracks again, then burn a proper unprotected version from that cue sheet. Or, if your goal is to only rip the disc without using another physical CD, then you can feed the tracks and the cue sheet to a piece of CD-emulator software and tell your ripper to rip that.
Of course, that was a long time ago. I'm sure that some of the ripper packages will, by now, have gotten wise to this and let you override the "don't bother to rip data tracks" feature.