I'm the same way. I've found that I need another person to keep me accountible so taking lessons has help me. I started drums this year and it's something I've always wanted to do and having a teacher give me things to practice and checking in keeps me going.

This may be old advice, and I can't speak for music or languages (where I myself have the same issue) but for woodworking and programming this is my experience: Once I get some idea for something I want to build, that becomes the goal of the project, not learning the skill itself. It could be carving a small model boat, or writing a sudoku solver, but at least for my part, once I get caught up in some project, I have a hard time letting it go. That's as opposed to if I sit down and try to systematically learn a skill.

Some suggestions for projects off the top of my head:

• Some kind of simple encryption/decryption method.
• A nice wooden box to put something nice in (possibly without visible metal parts)
• A sudoku solver
• Model car (maybe with wheels and movable doors)
• A little "river steamer" with a rubber-band driven "propeller" (don't know what the wheel on the back of a river steamer is called)
• A "peg solitaire" solver (because I was really frustrated at not being able to solve it)

The point is just to find something else that interests you, that can motivate you to learn the skill you want :) good luck!