The core concept of this cube is 'cards I think are sweet but bad'. There are a lot of cards that I like that aren't quite strong enough to see play in other formats (particularly Commander, my other format of choice), and many of the cards in this cube are ones which I have cut from my Commander decks. This cube is intended as a slightly lower-power format in which those cards can shine.

Themes to look out for:
WU - blink (Mistmeadow Witch, Momentary Blink, Ephemerate, Identity Thief)
UB - graveyard value (Pieces of the Puzzle, Forbidden Alchemy, Dig Through Time, Rise from the Tides)
BR - sacrifice (Mayhem Devil, Carrion Feeder, Captivating Crew)
RG - haste and combat triggers (Giant Adephage, Tectonic Giant, Fires of Yavimaya)
GW - go-wide (Wolfbriar Elemental, Kessig Cagebreakers, Angel of Invention)

WB - reanimator (Unburial Rites, Marshal's Anthem)
BG - creatures-in-graveyard (Old Stickfingers, Kessig Cagebreakers, Splinterfright)
GU - flash (Rashmi, Eternities Crafter, Prophet of Kruphix)
UR - spellslinger // pingers (Talrand, Sky Summoner, Thermo-Alchemist, Curiosity)
RW - voltron (Odric, Lunarch Marshal, Swiftblade Vindicator, Plate Armor)

Many of these themes cross into other colors - there is a fair amount of fixing, and the intent is for two-color decks to be tempted to splash a third color.