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There is indeed a vaguely similar episode of Carmen Sandiego: "Rules of the Game"
. The holographic head might be The Chief, and the climax of the episode does feature the ACME detectives playing as part of a giant chess game. Though the game is played on the site of a Hawaiian volcano, there isn't any fog present — however, earlier in the episode, the detectives warp into a foggy part of China and nearly get run down by some Chinese clay soldiers being rolled down a track.
That's Incredible Games, a gameshow on CBBC. The game I always remember best is the one where they're shrunk and have to swim through alphabet soup... The only episode on youtube is a celebrity special, here: https://www.youtube.com/watch?v=jYK-1ICTdYk

I was in some hotel once when I was younger and I remember seeing late on TV a really weird looking show. It had a bunch of kids on some elevator and you could tell it was an elevator because they kept having shots of the outside of the building they were in and it showed them in an elevator. They were talking to a giant blue holographic head and it was warning them about how they were going to face a challenge. The next thing I remember was the kids on a giant chess board and there was a black knight and his mooks on the board as well. The kids could only move spaces when fog shot out of the board because them the knight couldn't see them. The black knight caught some of the kids but eventually was outsmarted and the kids got away. The memory's really foggy so this may be a dream or two shows put together or something else. Anyone know what the show was?
Edited by Lunarcat