Not sure if this works but....

[Sparkle Ninja]

{Omniscience} + {Fireball} = board clear and kill? I'm thinking since you can play anything from your hand for free, does that mean you can make the x infinite? just something I was thinking for my Modern Izzet deck

[fj76ts4]

107.3b. If a player is casting a spell that has an {X} in its mana cost, the value of X isn't defined by the text of that spell, and an effect lets that player cast that spell while paying neither its mana cost nor an alternative cost that includes X, then the only legal choice for X is 0.

[Sparkle Ninja]

Awwww. I was hoping that would would work

[Pi]

Found the same problem with trying to use the {isochron scepter}. Ended up with a useless artifact the rest of the game.

[fj76ts4]

Barring the obvious denial-on-a-sticks, best ways to break an {Isochron Scepter}, IMO is:
{Odds // Ends},  {Research // Development}, etc.

Trust me, it works.

Relevant ruling, in case for some unfathomable reason you can't trust Testset:

12/1/2004: If the copied card is a split card, you may choose to cast either side of the split card, but not both. The split cards Fire/Ice, Illusion/Reality, Night/Day, Stand/Deliver, and Wax/Wane all have at least one side with converted mana cost 2 or less.

Sauce: http://magiccards.info/query?q=isochron+scepter&v=card&s=cname

[Younghawk]

Could I use the new ones from the RTR block like {alive//well}? And because of the fuse ability use both sides?