Wizard's Tower

The Wizard's Tower is the third official Oblivion download made available by Bethesda. It is available for download for the Xbox 360 and PC. The 17.6MB "Wizard's Tower" download costs 150 points on Xbox Live, or $1.89 for PC.

From the official website:

Located high in the Jeral Mountains of Cyrodiil away from prying eyes, this add-on makes the Wizard's Tower, Frostcrag Spire, become available. Packed with numerous useful enhancements, this structure will prove invaluable to magic-oriented characters.

Features:
 * A fully detailed tower for you to explore
 * A breathtaking view of Cyrodiil from the highest point in the land
 * Simple furnishings including a bed for leveling up
 * An indoor botanical garden with over 130 specimens... including Oblivion-native herbs!
 * Summon Atronach Familiars that obey your commands
 * Instant teleports to every Mages Guild in Cyrodiil
 * New Spell and Recharge vendor in the Imperial City
 * Fully upgrade the furnishings in your lair to suit your needs
 * Upgrade to a fully functional Enchanting and Spellmaking station with no need to join Mages Guild
 * Upgrade to a laboratory that buffs your Alchemy skill