The Omaha Project is probably the most infamous of all LNH Cascades. There's not a man alive who can explain what actually happened in it, but it more or less involved Mister Paprika's experiments to breach the Fifth Wall, and the reality-warping shenanigans that ensued. Read it, if you dare, here.
In Saviors of the Net, it was revealed that Dr. Net.ropolis was employed at the Omaha Project, and she had flung herself through the crack in the Fifth Wall, giving her an understanding of the nature of Looniversal reality.