Another idea would be to build a tarot deck with each card acting as a sponsor ritual. This can be used as a draw a card at random for a random effect that may help you or not, or the deck can be used as a divinition tool.
The idea to actually make a deck of cards is really awesome, and I encourage you to do that.
Then I would go and make the stats for the item something like this:
Deck of Tricks [-3]
It is what it is: And that's an old deck of 52 playing cards plus jokers.
One Time Discount [+1]: A deck of cards is a small item.
Luck of the Draw[-4]: As a standard action, you may draw a card from the deck. You are granted the powers attributed to the card. The powers last for 1 scene.
You've got to know when to hold 'em...: You may spend a fate point to have your current card last for one more scene.
...know when to fold 'em: Once per scene, you may spend a fate point to immediately draw a new card from the deck, after you just drew a card as a standard action.
Luck of the draw is modeled after modular abilities. Since you can't choose your power, I reduced the modular base cost by 1 point of refresh. You'd have to have powers worth approximately 3 refresh on any card, but not all of them have to be very useful or work together very well.
Example cards:
- evocation (offensive air specialization)
- Gaseous Form
- Document Forging (stunt) + superb deceit + "Mimic document" (the card acts as psychic paper (http://tardis.wikia.com/wiki/Psychic_paper))
- channeling (fire) + focus item (+1 offensive fire power and control)
- superb driving + superb scholarship + ghost speaker
- Diminutive Size + inhuman strength
- superb investigation + Psychometry + Quick Eye (stunt)
Well... you get the idea. You can easily change the 3 refresh, if you want more or less refresh on those powers. The superb skills are based on the mimic abilities power and can be replaced by higher or lower skill levels if you like, but I would always grant the maximum skill level your campaign allows. And of course those skills are not subject to the pyramid, they are extra.
Haru's got a good idea with Modular Abilities to represent the potential bonuses imparted. You might add "Human Form, involuntary change" to reflect that the benefits aren't always available, and availablility isn't under the character's control. And as others have mentioned, a "bad draw" would reflect a compel on the attached aspect (which could be "bought off", possibly by the mechanic Haru suggested).I'd kind of tied in human form when I reduced the modular abilities base costs. I would not so much create "bad draws", every card is kind of good, but a specific card might be extremely inappropriate for a specific situation.
The idea for the deck was that, as Pole had already said, the character would feel a compulsion to draw a card at a regular interval, with the card drawn affecting the character in a given way until the next card was drawn. One of the things that I'd considered is having the effect of the cards not necessarily be immediately obvious; for example, to everyone (including the person drawing the card) it would look like a normal playing card, and it would be left to experience to figure out what benefit (or malediction) the character gets. So the character may draw a card and say, "Well, nothing seems different." until he realizes that gouts of flame are spitting from his mouth. In addition to this, the entire deck appears blank until it's time to draw another card (so no stacking the deck!)Here's a possibility (spoilered for length):