Basically, after all of the traveling I’ve done, I grew tired of the Franco-Germanic area and aspired to travel elsewhere, which either requires an 8-12+ hour train or an expensive flight. So, I found a nice solution: night trains! Night trains are awesome. Within France they’re very cheap: I went to Monaco for a 20 euro reservation, which is what you’d pay for an inexpensive hostel. From southern France, it’s just a quick train to Italy, and there are also night trains that go between countries as well. I have some friends that took one to Barcelona for 30-40 euros, and I’m positive the night train to Berlin is fairly inexpensive as well.
The trains have rooms that house 6 beds, and yes, they are super cramped. I’m talking Titanic movie cramped.
But, all you’re doing is sleeping, so instead of staying up late and doing homework or other irrelevant things, get a good night’s rest so you can explore all the next day! (I’m joking, although if you are thinking of doing homework on this train, then forget about it. There were no common areas to just hang out in (at least on mine), and don’t expect to be able to sit upright comfortably in your bed.
Also, If you’re tall you may end up like this:
These trains usually leave late at 
night (mine left at 10 pm) and you arrive at your destination in the morning.
One thing to consider is that unless you buy out an entire cabin of all six beds, you’ll probably be sharing them with other people. So, if you have a group of friends that are obsessed with a card game and are refusing to quit at even 1 am, just be courteous of the people you’re sharing the cabin with and try to move out into the hallway. That doesn’t sound fun but it’s better that than pissing off some French women who will 100% use the entirety of their vocabulary to make you shut up (totally not based on personal experience). Also, it’s always good to be conscious of your things, but that’s a bit hard to do when you’re asleep. I cannot sleep with one eye open, and I doubt you can either, so I suggest getting a money belt/something similar so you can keep your passport and phone close to you without fear of prying hands. Get out there and see some far away stuff!