Always tough if players get a heads up they can just walk away from the temptation. Always easier to say than actually do. Every sin should have a negative attached to resisting. I believe ability scores are harder to resist than a magic item. Anyhoo, some brainstorming:
Pride: alternately a test that is below their dignity. The players need to shovel manure, etc. That's easy to role-play, but it's all about swallowing pride. Develop an abrasive (and invincible) noble who insists they lick his boots, wipe his arse, etc., before he'll release his captive who is essential to their quest. Each time the players balk, he cuts an ear, a toe, etc. off the captive, belittles the party as this is their fault, and he comes up with an even more demeaning task. The noble will go back on his word, say he's not done, they've not entertained him enough, and not release the captive. He'll insist on more tasks. If not done, he will eventually kill the captive, affecting the party negatively in a future venture. The point is to swallow pride to save someone as the tasks he insists upon, while demeaning, are never self-harming.
Wrath: like a Baldur's Gate II avatar, fighting it only makes it stronger, healing was the way to defeat it, and hints were given through religious dogma.
Greed: must sacrifice a valuable awesome item found during the trial, keeping it permanently and negatively affects one party member (e.g. a 2 point drop in a primary attribute, not game-breaking but it sucks). Will they harm a fellow party member to satisfy their need for this item? Alternately, could offer 2-3 awesome items (always less than # of players so someone is left out). The cost is a permanent hit on another player of their choice (the 2 point drop again).
Gluttony: it's all about taking more than you need, so doesn't have to be about food. Could be a dangerous path lined with treasure. A small amount won't affect the terrain, but every amount more than X increases the chances of something bad by a %. Alternately, could have food that restores ability scores lost previously through other tests. In doing so, the player will discover, be clearly informed, that once restored eating more can increase their primary attribute by, let's say 4, in exchange for a 2 point loss in something else of their choice. The twist is that gluttony is never rewarded. By taking more than they need, the penalty stays and the primary attribute is not boosted.
Lust: please don't go succubi. Lust is an intense, unnecessary, want for an object or circumstance. It's not always sex. Perhaps a Wishing Well test. It says it can boost a player's primary attribute by 1 and give them an awesome item. Each time it does, someone randomly in the world will lose an eye, arm, or leg, except for the characters.They can do this up to # of party members. Since this is a test, they get the boons (temporarily), and you can consider whether this affects someone in a future encounter or not.
Envy: one of the players receives a boon that protects them from a permanent drain effect that occurs each round while completing a task, crossing a puzzle board, etc. If he shares, the boon can be split into 2, leaving himself and one other party member (assuming 4) without. Players assume the penalties just go away, but leave them in until every trial is completed. They need to know the decisions have impact.
Sloth: taking the past of least resistance, the easy way out, is the lesson. The problem is that common sense sometimes says the easy way might be the better way. Maybe earlier in adventures give item that will auto-solve a puzzle, let's say a Passwall or limited Disintegrate magic item. Then let's put in a metagame puzzle to be solved. The twist is that there's an innocent stranger affected by their decisions. When they start the puzzle, a timer begins and the stranger, who is in a cage, will slowly be set free. However, if the puzzle is solved too quickly, the enchanted cage he is in will drop and he will be maimed by acid (lose a leg). Let's say 10 rounds. Each round, something bad happens to the players, and you need to make it hurt. Damage can be healed, but loss of coin, ability scores, items, etc., cannot. Will they take the easy way out and use the item to avoid harm to themselves, or will they take the harder path to save another?
