Three printouts on Flickr from Penn & Teller’s 1980’s BBS, the login screen of which helped you set up one of their many “Three of Clubs” card force tricks. Here’s how they described it in the back of their Cruel Tricks for Dear Friends book from 1987:
Got a modem? Call MOFO EX MACHINA, the bitchin’est BBS in the jungle. Just call 212-764-3834, hit ENTER twice, and type the password MOFO (300 or 1200 baud, 8 bits, 1 stop, no parity).