The Dominators/Upfront/Trilogy Party 1989 was held at a school in Randers, Denmark by Dominators (c64), Upfront (c64) and Trilogy (amiga). The entry fee was set at 80DKR with invitation, likely more without. The first prices in the demo competitions were announced as 5000DKR, which was REALLY a lot back then! The party was a large success, and about 4-500 people from all over Europe attended. Kefrens and Arcane held a Sprite competition.
Amiga results based on party report from Stolen Data #2 (Paper). According to the report, "7 more demos took part in the competition, but they did not reach a very high standard." C64 results based on Dominators+Upfront+Trilogy_Results.txt from ftp.scs-trc.net.
Further reports in BYG #2, Expose #4, and Pirates #8.