The deck is no more, the discard is looming over the playing field, and people have been ranked by points (or whatever you were using to keep score). A winner is (possibly) crowned and any losers are promptly humiliated. Well, now what?
Why, a minimalist French play of course! *rimshot* That is, the Endgame. This part of the game is often skipped, especially during parties, because it's a bit of a pain to set up and isn't surface exciting like the main game. But it is important! Let's be frank: a good deal of the cards you guys created aren't quite Hall of Famers. Along with the more obvious QA problems, the game you just played may have revealed balance problems with other cards. The Endgame is where you get to fix those problems.
Spread the cards out on the table, and whisk away any remaining blanks. Depending on how you roll, the players can vote for which cards they want to excise, pick up a certain number of cards they want to keep, or some other bizarre system with the same effect. Toss the losers in the Suck Box and shuffle the rest into the stockpile.
Usually. Since this is 1000 Blank White Cards, you can certainly mess around with even this phase. "If this card is in your hand at the end of the game, you may keep one more card than usual." "Instead of removing cards, they must be switched with cards currently in the suckbox." "Only the top three players decide what stays or goes."
The obvious opposite of the Engame is the Pregame.