Artifact Question

[Arryn]

incognito said:
1) Can artifacts change the course of the game (examples welcome)?

With the possible exceptions of the Ark (for dominion spread) and the Gift of Kurgi, I'd say no. The effects of most artifacts, while nice, simply aren't powerful enough to be that dramatic, and don't approach the power of some of the global rituals, which can and often do change the outcome of a game.