Comics Jams are when a bunch of people get together, hang out, drink (or not), talk, and draw comics. They're a pretty neat way to meet other people into comics, and they allow people to draw really bizarre stuff.
Generally what happens is that each person draws a panel of a comic, and then passes it off to the next person who continues the story. It's sort of like an exquisite corpse thing.
While I think they are great for the people who are at them (meet new people! practice drawing!), I think that reading them afterward is a less satisfying experience. The comics may feature some nice art, but the stories are just insane mashes of ideas that don't lead anywhere, sentient hamburgers giving oral sex to girls, or comics that remind me of this song. What? I mean....
So yeah! At the very least, I hope these sort of publications inspire people to create their own comic jams. More comics is more better!