In English, there are "classic" knock-knock jokes (1) based on puns, and two-line question-answer jokes (2) with witty punchlines:
xxx: Knock knock!
yyy: Who's there?
yyy: Lego who?
xxx: Lego to the movies!
Q: Where do astronauts hang out?
There are more varieties, of course, but I'm only interested in these two, as they both are concise and don't require a setting or a backstory.
Question: Are there similar jokes in the Russian language that are short, based exclusively on puns and wordplay, and that are currently popular? Some examples would be great. Thanks!