Carcassonne Central

At the start of the game a stack of counters of all colours is put to the side of the playing area.

A regular meeple of your colour can be played as a spy but each player can have only one deployed spy at any one time. you deploy it "legally" to any feature standing on a token of another players colour taken from the collective supply, designating it as a spy "pretending" to be a meeple of that colour.

when the meeple joins the feature it counts with the meeples of the colour of its token for majority, but when the score for the feature is tallied the spy siphens off a proportion of the points for its actual colour

say red and blue each had 2 meeples in a city and black played a spy on a red token and later connected it to the city, on completion of the city red would count 3 for majority, blue 2 and black 0. red would score for the feature, blue would get nothing. Black's spy would then siphen off a proportion of the points (in this case 1/3) for the black player and red would get 2/3 plus any of the fractions or rounding up of points.

and / or

at the start of the game each player (got the idea from a game show) recieves 2 single sided tokens with the word steal / share on them

An alliance between 2 players is formed over a feature.

At this point each member of the alliance places one of their tokens under one of their meeples on the feature.

when the majority is counted for the feature both allies are counted collectively against any other players.

Presuming the alliance wins majority and collects the points for the feature, the allies then turn over their counters.

if both counters read share both allies score half points for the feature
if one reads share and the other reads steal, the "steal" player recieves full points for the feature the "share" player recieves nothing
if both read steal, neither player scores any points for the feature.

These are both really interesting.  I'd like to see them in action.