Ask HN: How do you list bad projects on your resume?

Unless the gig was very short (and so can be safely omitted), there's no reason to be coy about simply listing, in objective terms, where you worked and what you did. If you like, you can simply go into more detail (lines / bullet points) about the positive experiences, and less detail about the negative ones.

Also, you can safely "couch" negative experiences (like being fired for no particular reason, or effectively forced to quit by some domineering jerk) in various ways, like for example when it comes to listing references -- because it kind of looks bad not to have at least one reference for recent gigs, at least -- to simply not give the phone number of the obtuse junior manager which was the main reason you quit anyway, but listing instead a compatriot developer, perhaps still bound to his desks with golden handcuffs, but who knew the deal about what was going on in that sorry place, and won't be shy about putting a positive spin on your time there.

Basic idea being is that if you must convey negative (or simply lackluster) information about a former employer, it's vastly better to let someone else do it for you.

Or if you must deal the poop yourself, at least try to soft-pedal it so that the basic truth gets across (while still not sounding like you're nursing a grudge): so instead of saying "OMG they were so clueless", true though this may be, you can say things like "well they weren't really interested in trying new ways of doing things, so ultimately I felt my talents were underutilized."

To answer your question though...

Try to quantify what kind of impact your work had to either the top or bottom line and avoid talking down the team or technology used.

Barring that, talk about what kinds of problems the project solved and what it helped the team/group/company accomplish.

If you can't even do that, then I would just mention the workplace and job title and talk up other parts of your history and/or skill set

Something like: "Despite my numerous attempts to convince the powers that be to implement $solution using $awesome_stuff, the policy remained the same: stick with $ancient_pile_of_dog_poo. But a job needs to be done, and so it was."

This has the advantage of suggesting that you will do what you're told - not neccessarily without trying to have your say first, but eventually, the job gets done.