The Magic Library is the idea for an adventure that can easily be adapted for parties of any level.
Print out the map of the library (shown below in low resolution).
The adventure should follow another quest where the party have rescued someone or done a good deed that deserves reward (plenty of scope for this in a D&D or other role-playing adventure!)
The person they've rescued tells them of a secret library which contains a magic book that when touched to another book with the correct word uttered, will bring the other book to life! They give the players a map of the library and say that they are to visit the Trade section where they will find a book with a golden cover (that is literally made of gold) called Dreams of Riches.
They are to find this book and then head to the Magic section where they will find a small paperback book called simply What is Real. When the 2 books touch and the players say the magic word, all the amazing things in Dreams of Riches will become real.
Players then set off on a quest, slaying monsters and discovering the location of the Magic Library.
When they enter the library they are drawn to open other books but find that when they open them, the words dash and dart in front of them so they cannot read them. They must pass a Difficult intelligence check to put down any book they have picked up, as it feels stuck to their hands.
If players say the magic word while holding What is Real then any books from the Magic Library that are within 1 mile of What is Real will come to life, creating a new mini-universe that players find themselves in.