People call Minecraft a "survival" game. But really, there isn't much survival to it. Sure, you could spawn on an island, with little ways to get food, but just a single tree, and you will be boating out of there and to the mainland. Or you could stay, and just go mining and make your base there. It isn't really surviving. Even in "Hardcore" mode, where you cannnot respawn if you die and all mobs are a bit harder, it can get boring. You usually die because of an overwhelming about of mobs, or because you fell from a large hole you dug to the bottom and died (my older brother Jonathan).
But now, with mods, you can make things funner, harder, and sometimes even harder to survive. There is a modpack (a bunch of mods that is put together) called Crash Landing Survival. This modpack also comes with a map. It has no specific story, but you have crashed, and it is your job to survive this barren, dusty, land. You cannot waste time. You have to watch your hunger and tempature, so staying out in the sun or near the fuel leaking from the right engine is not an option. You you won't start out with any water. You will die if you don't work straight away. First off, you get a book with a bunch of "quests", which give you goals and instructions to complete those goals. And when you complete a goal, you get a small reward.
Now, this modpack is very sciency. You have to get dirt by growing a tree you got from the first quest. This seems impossible. But, actually, it isn't. You can convert saplings, and later, leaves (when you get your hands onto some iron) into dirt by fermenting it in a barrel! With the dirt, you can put that together with one of the empty water bottles left over from your small list of provisions, to get dirty water. This is undrinkable, so you have to clean it. You just smelt it using some of the items you got from the start.
The whole modpack is planned out from beginning to end, with only a very small amount of bugs. You will eventually end up building machinery, and creating smelterys, infinite stone generators, and even a pressure chamber! And the best part is, you don't really have to know anything about the mods in this modpack. The questbook guide you all through it.
Of course, thirst and hunger aren't the only problems. At night, there will be creepers, spiders, and skeletons. But these vanilla mobs are almost not even there. There are going to be nearly fifty mobs outside your door every night, each a variation of a vanilla mob. It might actually take a while to get a sword, too. Another cool feature, is that you can sift the dust, to get some nice survival items. There is about a 15% chance you can get stones from a single block of dust, and you can use four of those stones to make one cobblestone. You use the cobblestone to make a furnace, in which you clean your dirty water, before you run out of the supply you already have. You can download it here.