The Feast of Victory was when Sumner invited the Heroes of the Realms back to his tower to come and have a feast after killing Skorne.
The tables were placed from over the Underworld portal to under the Shard Window, over the Desecrated Temple. Sumner sat over the Portal there, and conjured delicious Food found in the realms, including buffets of Apples, Cherries, Bananas, Pineapples, Watermelons, and large portions of delicious, juicy meat.
Unfortunately, the feast was interrupted when Garm's undead army started wailing away at the tower, eventually beaking it down. The feast was put on hold until the heroes killed Garm, and then it resumed.