Might as well go for something nutty...
Jubilee
Action - 8D
-
Trash this. Gain a Gold, a Duchy, an Action costing up to $4, and a Curse onto your deck.
Planning an awesome Jubilee takes some time, and you'll most likely go into Debt because of it. However, it will certainly be a wonderful, colorful time, and you'll certainly attract some big money, a positive reputation, and maybe even some new citizens to add to your workforce. And most likely a giant hangover that you'll be cursing the next day.
Yeah, I have absolutely no idea how much this should cost, as I haven't had a chance to playtest it. On the one hand, you are gaining a Gold and an Action that you'll be able to use really soon. And you are also gaining a Duchy. However, that Duchy is going on top of your deck as well, along with a nasty Curse. I just put it at 8D for now and will see what everyone else thinks.
Oh, and I just realized: the order in which the cards go onto your deck are the same order in which they are gained, so the Gold goes on first, then the Duchy, then the Action, then the Curse on very top. I should probably reword this to make the order clear (along with the fact that all four cards are gained onto deck).