Wormhole

All kinds of infinite combos, with Gutless Ghoul sacrificing Eternal Witness, et al, then sac lands and Second Sunrise to bring it all back untapped, and Eternal Witness brings back Second Sunrise. Use Faceless Butcher on Eternal Witness for added effect (once when EW comes into play, and then FB's CIP ability targets EW, and sac FB after stack clears). Countryside Crusher can be made huge and blockers removed from game with Faceless Butcher. Use tutoring for whatever necessary combo is closest to realization. Use Tormod's Crypt to prevent opponents from benefitting from Second Sunrise. It's complicated, but fun and in multiplayer games it is sneaky and then it's over for all the opponents.