Unexpected Results is a rare Sorcery card from Gatecrash (GTC), collector number 203. Current market price: $0.51 (foil $2.21), TCGplayer market prices via Scryfall.
Shuffle your library, then reveal the top card. If it's a nonland card, you may cast it without paying its mana cost. If it's a land card, you may put it onto the battlefield and return Unexpected Results to its owner's hand.