Write a video game. I tell this to everyone who wants to learn to program. Forget web development, initially (unless you want to learn HTML5/Canvas to build the game, which is not a bad idea at all). Game development is probably the best way to learn to program because it's fun, you have some sort of goal, you can be creative, and you have to learn a great mix of skills -- graphics/sprites, sound, timing, interaction, math, physics, etc.