I've been teaching myself French on Duolingo for almost two years now, and have gotten to the point where I can read the untranslated bits in English novels. Go me!
After watching the Beforeigners, I've started teaching myself Norwegian.
What I like best about learning these languages is the grammar -- it's very cool to see how other languages work. For instance, in Norwegian, if you want to use an indefinite article (a spider, a horse), you put the word en or et in front of the word -- en edderkopp, en hest. Contriwise, if you want a definite article (the spider, the horse), then you move the en or et to the back of the word -- edderkoppen, hesten.
So "a child" is "et barn," and "the child" is "barnet."
French grammar is very close to English grammar, unsurprisingly, so the interesting part of that is seeing how the French wordstock has influenced English (and v.v.) over the centuries.