I don't know where my obsession with museums came from but they're the most interesting and entertaining places that I've been which is super surprising. In grade 7 I was taken to the Brisbane Science Museum with the class and that was the first time I'd ever been. I was hesitant at first because I thought it would be boring but you would be surprised. Science and history museums are my most highly recommended places to go, with art being my least favourite (how many different photos of boobs and naked babies are there?!) however it is all dependent upon individual taste.
There are museums all over the world and multiple in every place, so take your pick. When I was travelling Europe I came across one in Salzburg, Austria and I spent an entire day in there and could probably spend another day in there too. They are never too expensive and usually you'll lose track of time as you take the time to read every thing you see and interact with anything they offer. I like the interactive things in the 'space' section where you can stand on a weight scale and it'll tell you how much you'd weigh on the different planets. And the extinct animal section which always shows you the strangest creatures.
Take your time and try to take everything in, you'll learn something without realizing and even if you dont remember any of it, you still have an awesome time.