It's easy to get free lives in the 3DS' excellent Super Mario 3D Land, especially if you go to World 1-2 and hop on the right Koopa shell.
YouTube user Arctic Extras found what is either a glitch or a wonderful Easter Egg that has generated at least 885 free lives for him so far. He makes one well-timed hop, and it's all auto-bouncing and fee-life-harvesting from there.
Design mistake? Bug? No. I declare this to be a feature! Just like the infinite lives features in classic Mario games.
SUPER MARIO 3D LAND INFINTE 1-UP GLITCH! [YouTube]