To directly answer your question, no, there isn't really a single site where you can ask any question you would find in any interview. It depends on the question - there are a lot of different things that can be covered in an interview, and many of them will be inherently specific to your particular vocation.
As mentioned in the question comments, The Workplace might be the best candidate for general questions ("What are your weaknesses", "Where do you see yourself in five years"), although you'll still need to make sure that you have a real, answerable question.
For software developers, and for questions that are not directly about code but that are still software-related, the Software Engineering Stack Exchange does allow some interview questions, although again you'll want to make sure it meets their requirements as they seem to get a lot of poor examples. Stack Overflow would likely be the best candidate for code-based questions, or maybe Code Review if you just want to assess what you came up with.