Disk-designing contest organised by Swiss Cracking Association. In their demo SCA Competition!, they lay out the rules:

SEND US YOUR MOST BEAUTIFUL 5.25'' OR 3.5'' DISKS. PAINT IT, SPRAY IT, DYE IT OR PUT SOME ORIGINAL STICKERS ON IT. THEN WRAP IT IN A PAPER WHICH CONTAINS YOUR ADDRESS. THE WHOLE BUNCH HAS TO BE PUT INTO AN ENVELOPE AND SENT TO THE FOLLOWING ADDRESS : PO-BOX 470 / 8037 ZUERICH / SWITZERLAND. AFTER HAVING DONE THIS, YOU LEAN BACK IN YOUR CHAIR AND WAIT FOR YOUR PRIZE... 1ST TO 3RD PRIZE: A DINNER WITH THE SCA-CREW (ALL TOGETHER, IN ZURICH) 4TH TO 10TH PRIZE: AN SCA T-SHIRT (100% COTTON, SIZE: S,M,L OR XL) 10TH TO 25TH: AN SCA-STICKER OR AN SCA SWAP-DISK.

Four entries from the competition can be seen here.