A Slam Jam thread is a thread which has videos revolving around the song "Space Jam" from the Quad City DJ's for the Warner Brothers movie of the same name, Space Jam.
Use of derail
Whenever someone mentions the term "slam jam" or "slam", a current poster derails the thread into a Slam Jam thread.
Arin's Slam Jam
Arin's Slam Jam is a meme mixing a Slam Jam thread and the Game Grumps derail. A poster posts a video containing the final moment from the NBA Jam episode of Game Grumps, in which Arin Hanson epically slam dunks the ball, causing the backboard to break.