Clue-Chess

Essentially just Clue + Chess. This one has the benefit of being able to be played by more than 2 players. It is a little confusing, but in the abstract, the Clue and Chess pieces share the Clue board, with the Clue player(s) trying to solve a murder while the Chess pieces hunt them down.

Rules: There are two groups of players: Clue players and a Chess player. There is only 1 person who can play with the Chess pieces and either 1 or 2 people who can play with the Clue pieces.

The game begins, as in Clue, with a character, room, and weapon card being randomly selected. These represent the case the Clue player(s) have to solve.

Each player takes one turn every round, even when there are more than one Clue players.

Clue player(s):
The goal of the Clue player(s), as in the original game, is to solve the case selected at the start of the game by process of elimination. If one player is playing Clue, they control all 6 pieces. If two players are playing Clue, each controls 3 pieces. The players all share one clue guessing sheet and work cooperatively.
During each Clue player's turn, that person rolls a die. Then, they may select (individually, for each piece) to either stay in place or move the entire roll of the die. As long as the piece doesn't end on a space shared by another piece, it may move through both Clue and Chess pieces. Also, on up to (only) 3 turns, the player may move any number of their pieces through one of the secret passages as that piece's move.
After having all movement is finished, if the player has any pieces in rooms, one of those pieces may guess a possible combination for the case, as in Clue. The guess must include the room that piece is in, but as in Clue, any other players that are being guessed must be immediately moved to that room. The Chess player, who holds all the cards besides the 3 case cards and whatever other character cards have been set aside, must show the Clue player(s) only one card to disprove their guess. This card is set down exposed on the table and may never be revealed again. After a guess, that exact combination may never be guessed again by any player. Each piece can only guess once in a room and must move back into the hallway before guessing again.
A player may, instead of making a guess as to what the case file contains, may guess which of their pieces is being hunted by the Chess player. This guess does not have to be made from a room and yields only a simple yes or no answer. If the guess is correct, the Chess player replaces the character card and randomly chooses another target from that players possible characters (the same character may be drawn again).
At any point during their turn, a Clue player may make an accusation, definitively guessing what cards are in the case file. If they guess incorrectly, they are out of the game.

Chess player:
The goal of the Chess pieces, like in Chess, is to capture a specific member of the opposing team(s) (in this case, the Clue pieces). At the start of the game, after the case cards have been set aside, the chess player randomly chooses one character card corresponding to each opponent and sets it aside. It is the goal of the Chess player to hunt down and capture that piece (or pieces) by either landing directly on their square in the hallway or enters the same room as them. If the critical piece is captured, the player in charge of that piece is out of the game. Other Clue pieces may be captured and removed from the game as well, but the Clue player stays in the game, and may still guess captured pieces, although those pieces are for all other purposes out of the game.
For the purposes of this game, the staircase box in the middle of the Clue board counts as a room, in which the Chess pieces start. The door is as wide as the wall facing the "Hall", and is where the Chess pieces may exit from at the start of the game.
The Chess player starts with a queen, a bishop, a rook, and a knight in the center staircase and may move one piece a turn, as in Chess.
When entering and exiting a room, the piece's move must land them on the square directly inside the door(s). While the pieces may not move past each other or the Clue pieces, the knight may jump over both Clue and Chess pieces. Chess pieces may never use secret passages.

Verdict: Amazing. The level of strategy involved for the Clue player is hard to believe, and though the Chess player(s) have a more straight-forward objective, he or she has to try not to let their opponent(s) know what their target is. It very unrefined, and has changed a lot since my sister and I first came up with it. It probably still needs work. But it's fun.