Here's the first of the promised 10th Edition card highlights.
Above is a picture of Crucible of Worlds. I have available copies of this card in both normal and foil formats. The card was originally introduced in the Fifth Dawn expansion set, and has been imported into the Core Set with 10th Edition.
Crucible of Worlds is an Artifact that simply allows you to play Land cards from your graveyard. While this may not seem like much (especially to the Magic non-initiate), there are all sorts of very amazing uses that this allows for.
First of all, it's great defense against a Land-destruction deck. Has your opponent Stone Rained your only Island? No problem - just play it from your graveyard next turn and you're back in business.
Secondly, it's great for retrieval and re-use of Lands that require sacrificing to use a special ability. For example, in 10th Edition there is Quicksand, a Land that can be sacrificed to give target Creature without Flying -1/-2 until the end of the turn. After you've sacrificed it, it's in your graveyard. Now with Crucible of Worlds you can play it again next turn. Or if you REALLY want to get nasty, sacrifice it for its ability before you play a Land, then play the Quicksand from your graveyard and sacrifice it a second time! Now you've given that poor Creature -2/-4, thereby killing the majority of Creatures in the game. It's also great with Archaeological Dig from Invasion - a Land that can be sacrificed to add one mana of any color to your mana pool. Great combo with the Crucible in a multicolored deck.
Thirdly, there are several Spells and Abilities that require you to sacrifice Land(s) as a cost. Again, retrieving them is no problem with the Crucible. Like the Arcane Spyglass from Darksteel that allows you to sacrifice a Land to draw a card (and put a charge counter on the Spyglass - removing three charge counters also lets you draw a card). Just keep feeding the same Land to the Spyglass once a turn, and bring it back again next turn!
Fourthly, they work great with the Cycle Lands from Urza's Saga or Onslaught. Cycle that Barren Moor to draw a card (this sends the Barren Moor to the graveyard), then play it from your graveyard with the Crucible.
Finally (and these are just the uses I came up with off the top of my head), this is great for using Land cards as discards when a Spell or Ability requires discarding as a cost. Discard the Land, then play it from your graveyard. For example the lovely counterspell Foil from Prophecy allows you discard an Island and another card instead of paying its mana cost. Sneak in the Foil to counter an opponent's Spell, then rescue your Island from your graveyard next turn!
Really, the card is incredibly useful, and it's no wonder that it has proven so far to be one of the most popular of all the cards in 10th Edition.