Rod of Spanking – Unhinged uncommon. See, because the card requires a target player to "give thanks". Get it?
Mausoleum Turnkey – Ravnica: City of Guilds uncommon. Cards like Mausoleum Turnkey really shine in multiplayer Magic, because it involves an opponent's choice... but you get to choose the opponent!
Horn of Plenty – Mercadian Masques rare. A "horn of plenty" is a real thing: it's "a goat's horn overflowing with fruit, flowers, and grain, signifying prosperity," according to Answers.com. It symbolizes the horn of the goat that suckled Zeus, which broke off and became filled with fruit.
Puppet Conjurer – Shards of Alara uncommon. The homunculi created by the Puppet Conjurers perform a valuable role in Esper society. They're clerks, scribes, and in some cases, testaments to their owners' majesty.
Arcane Sanctum – Shards of Alara uncommon. It's never cloudy at the Sanctum Arcanum; the Vedalken that live and study there have enchanted the clouds to create an area of permanently clear sky so that they can study the Filigree Texts more clearly.
Courier's Capsule – Shards of Alara common. The Esper control of winds is so powerful, they send messages composed of compacted wind! The art for Courier's Capsule shows what the recipient sees moments after opening the capsule.
Punish Ignorance – Shards of Alara rare. You've got Ertai on Dismiss: "There is nothing you can do that I cannot simply deny." You've got a Vizier on the Mercadian MasquesCounterspell: "Your attack has been rendered harmless. It is, however, quite pretty." But on Punish Ignorance, Indra might provide the most dismissive quote of all: "Amateurish. Nearsighted. A waste of my time and everyone else's." Ouch!
Macabre Waltz – Dissension common. Originally designed with the discard as an additional cost, Macabre Waltz was changed upon final printing. The concern was that having the discard as a part of the cost was confusing; would players try to return the card they had discarded? Ultimately the final version solved that problem and was better against counters to boot!
Time Warp – Tempest rare. One of the most popular and well-received cards from the Tempest set, Time Warp harkened back to the legendary power cards of Alpha/Beta. Specifically, providing players with an extra turn was identical to the Power 9 favorite Time Walk. The Tempest version proved to be far less volatile, though it did see play in the Turbo Land decks of Extended.
Wild Swing – Shadowmoor uncommon. The templating for Wild Swing was originally very complex. Versions were discussed that countered the spell if a target was made illegal, required players to roll a die to determine the winning target, and/or could hit enchantments. Ultimately this final version was adopted, a perfect fit for the color red!
Energy Tap – Legends common. For a long time in the color pie, blue was afforded the ability to make lots of colorless mana. The thinking was that because blue was loosely associated with artifacts, the mana generation was relatively flavorful. Ultimately the color has shifted away from that ability, but you can see it on such cards as Energy Tap and Apprentice Wizard.
Lead-Belly Chimera – Visions uncommon. The Chimeras were a cycle of four cards in the Visions set. Designed to evoke a feeling of mechanoid creatures that could combine with one another to make a singular, large monster, the 2/2s each had a sacrifice ability that gave a permanent +2/+2 counter to a fellow Chimera tribe member. In the case of Lead-Belly, it also bestowed the gift of trample.
Where Ancients Tread – Shards of Alara rare. The answer to the question of where ancients tread is pretty clearly "wherever they want to."
Drumhunter – Shards of Alara uncommon. As the humans of Naya move throughout the enormous forests, they use drumming to communicate. The roots of each of the trees has a different sound that they can instantly identify, letting them communicate their position with remarkable accuracy.
Qasali Ambusher – Shards of Alara uncommon. Once, the Cloud Nacatl had a vast civilization in the treetops. But the Cloud Empire has withered as more and more Nacatl have gone wild. The last remaining stronghold is Qasal, ruled by Timus the Orange.
Keeper of Progenitus – Shards of Alara rare. According to the elves of Naya, the Breaking of the World was caused by the great Progenitus, who tired of the world and unleashed five storms: Wildfire, Earthquake, Windstorm, Flood, and Void. After Cylia was blinded, she saw Progenitus's true form as a five-headed hydra.
Cylian Elf – Shards of Alara common. The Cylian Elf is not from an area called "Cylia"; it's an elf that follows the teaching of the first elvish high priest, Cylia the Witness, who was at the Breaking of the World.