Beyond the major faction questlines, Cyrodiil offers a plethora of miscellaneous activities and smaller side quests to keep you engaged. The Arena in the Imperial City is a prime example, allowing you to test your combat skills against various opponents in gladiatorial matches. Winning matches earns you gold, fame, and eventually the title of Grand Champion. This is an excellent way to earn money and improve your combat skills.
Other activities include exploring the numerous dungeons, Ayleid ruins, and caves scattered across the landscape, each often containing unique loot, lore, and challenging enemies. You can also engage in alchemy, enchanting, and spellmaking to create powerful items and spells. Look out for smaller, unmarked quests given by NPCs in towns and on the roads; these often lead to interesting mini-stories and unexpected rewards. collect Nirnroot, explore the Shivering Isles (if you have the expansion), and hunt for rare books and artifacts. The world of Oblivion is vast, and there's always something new to do.