From SlamCharlotte's perspective (this has nothing to do with PSi):
Our gauntlet slam is our fun slam. It's where poets don't have to worry about points b/c that part of our season is over.
So we throw down the "gauntlet" and have fun. The only thing on the line is laughter and a cash prize.
We have 4 or 5 rounds (depending on time) that we change up every year. We've done a gauntlet slam for the last 5 years and our poets and audience love it.
The structure is totally up to the person creating the event. I don't know that there is a format per say.