The lights are on
This glitch/cheat will max out all your skills to level 100. It makes your character incredibly powerful, but that can take the fun out of the game.
Step 1: Get the book titled Oghma Infinium. You can obtain this book by completing the Hermaeus Mora daedric quest.
Step 2: Go to a bookshelf in any house that you own, and with the book in your inventory, activate the bookshelf.
Step 3: Instead of storing the book on the shelf, read the book. Choose any of the paths offered.
Step 4: Back out of that screen,(to your book inventory), and then put the book on the shelf.
Step 5: Exit the menu, and then select the book on the shelf. Confirm the "read Oghma Infinium". DO NOT ACTUALLY READ IT ONCE CONFIRMED. Simply choose "do not read". Proceed to take the book off the shelf.
Step 6: Repeat the process starting at STEP 2, and from there repeat these directions until you have reached the level you desire.
Notes: I recommend saving before using this cheat, because a mess up can have a permanent effect on your character. I have used this glitch with one of my characters and I can kill a Dragon or Giant with a single blow.