Hi Priscilla, great question!
"carved-out block of time" simply means scheduled time.
This text is talking about scheduling time to relax and go see a movie.
Another way you could use this expression is to say: "I am very busy tomorrow, but I can carve-out some time to have tea with you." You can see that it really means the same thing as "schedule".
This expression is certainly used in American English, but I am not sure how common it is in other English speaking countries.