Bruce is talking to a co-worker.
Bruce: Pretty good. You?
Jose: Good. Any plans for the weekend?
Bruce: Yeah. Actually, I'm taking up the harmonica. My first lesson is tomorrow.
Jose: That's cool.
Bruce: Do you play any instruments?
Jose: I play the guitar.
Bruce: Nice. Let's start a band!
Jose: Ha ha, sounds good.
Key Point: You can say "I'm taking up _____." to say you're starting a new hobby.