In the past I have worked on a Rummy Civ game. There are three ages and players collect cards using the Rummy mechanism of pick up, put down (meld) and throw away (discard). There are 4 suits representing military, economy, culture and science. These have cards ranked from 1 to 5. So using the Rummy mechanic you can place runs of the same colour or sets of the same colour – building your military strength, economy etc…
However, there is a twist in each suit of cards there are neutral, attacking and defending cards. The neutral cards have no effects. The defensive cards create protection against the attacking cards when on the table as part of a meld. The attacking cards can be played during the meld phase and once used are discarded.
Military attacking card allows players to steal cards that have been placed in melds by other players.
Economy attacking cards allow players to force a trade with another player – player may ask for a certain suit and give a suit of their choice to the other player (no suit then go fish!)
Science attacking cards allow players to look at the top 3 cards of the deck and keep one. The player may decide to place both cards back on top of the deck or on the bottom of the deck.
Culture attacking cards allow the player to take a card from the discard pile.
Once a player has no more cards in their hand then the first round is over and the second Age – with the new Age deck – starts.
In the second and third ages cards may be added to sets from previous ages or may be melded into new sets.
Scoring – some kind of modified Knizia scoring system where being strong in one suit is not necessarily advantageous.
My new card game idea is a hidden identity trick taking game. Players have hidden identities and maybe working together. Cards represent regions that the players want to control. The cards have some indication of what ‘faction’ they benefit. By winning tricks players start to control areas on a map. This could be a cold war type game or even be themed to something like A Game of Thrones. Still mulling over the idea in my mind.
**edit** It could be that during a round players have to declare their allegiance but this could change from round to round. So, no hidden identity but rather a guess as to who might win the trick. Points are given (or rewards – or control) to the successful group.