I kind of created this new game in Oblivion called Arena Hardcore Mode. The game starts right before you leave the sewer. Make your character, then go up to fight in the Arena.
Rules
1: Any method of combat is allowed. Magic, archery, strong weapons, summoning, potions, you name it. There are no rules.
2: You can NOT leave the general area of the city. The bandit camp across the lake when you get out of the sewers and the town along the bridge outside the great city are the only exceptions.
3: You are allowed to buy weapons, items and spells inside the city, but nowhere else.
4: Your mission is to go through the entire Arena like a god. Remember, you only get one shot. If you die in the arena, you have to start all over with a new character.
5: If you die at the bandit camp or die trying to fight the law, you have to start all over with a new character.
...That's all I can think of. Going through it three times. My first time was with a brightly colored Wood Elf who used a one-handed weapon and a shield and fought with poisons. ...He could not even beat the first opponent.
My next player was a rather ugly looking Kajiit archer who also dealt in poisons, and prefered to use a bow as her only weapon. She fared a lot better, managing to make it all the way to the female Orc and her glass hammer at the end of Warrior Rank before pushing up daisies.
My current character is a chubby-faced Nord who uses a big warhammer and fire magic. He's at Myrmidon rank right now and so far that warhammer is doing some legit beatdown. I did have one close call though. I fought the Redguard who either uses a mace or a sword, and I kept fiddling with my spells trying to get them to work, and I came REALLY close to dying that fight, but I got lucky and beat him.