Ask HN: Motivating projects to learn functional programming languages?

I've always wanted to learn a language like Haskell, Lisp, Erlang, etc., but I've never been able to motivate myself beyond the first few examples because I haven't found a way to apply it. I've found that the best way I learn is to pick up a project and learn the language/tools/API as I go along — it's strange, but it's much easier for me to lose myself working on a project than an academic exercise. I start putting all the pieces together and eventually everything just "clicks"; I reach an epiphany and can start thinking in the language.

Can anyone else relate to this? How do you learn less "practical" languages like these?