What is "underwater basket weaving"

n. (context idiomatic English) An easy and useless college or high school class.

Underwater basket weaving is an idiom referring in a negative way to supposedly useless or absurd college or university courses, and often generally to refer to a perceived decline in educational standards. The term also serves as an intentionally humorous generic answer to questions about an academic degree. It is also used to humorously refer to any non-academic elective course, specifically one that does not count towards any graduation requirements.