Maybe Fate Accelerated? You can jump right in, just pick a High Concept (What the character is mainly about), maybe a Trouble and approaches (how you approach problems) and leave the rest to fill in. You have Fate points, which you spend to improve rolls and which you get by getting into trouble / adventure. The players have more ability to affect the story than in D&D, and is usually easier to get into for beginners than for experienced rpg players - check Book of Hanz for tips.