Can you make up a similar question that doesn't reference Douglas Adams' work at all?
What is one two-digit number that can be written with three tens? The answer is '42', which when written in binary is '101010'.
Here is another one: What is a number which can also represent the wildcard for everything? The answer is '42', which when converted to ASCII, is the asterisk.
What is the funniest question you can ask whose answer is 42? Here's a funny question whose answer is 42:

What do you get when you multiply six by nine? (The answer, according to "The Hitchhiker's Guide to the Galaxy" by Douglas Adams, is 42, although this appears to be a joke based on a misunderstanding of the question.)