Craftybit's OBSE. Requires Oblivion Script Extender. The one from 'Planet Elder Scrolls' is newer I believe, so get that one. If you want some new homes go to 'Oblivion Real Estate'. You can find houses ranging from castles to floating barrels to actual sailing ships! Mart's Monster Mod is good if you think the vanilla enemies are piss weak and you can be asleep and still beat them. Don't forget the Oblivion Mod Manager. There's also a physics mod and a zombie mod out there too.
I've played long hours on Oblivion just with mods and doing pretty much jack stuff on the real game, companion mods, house add-ons, topless mods :3, hell, even a beta pirate mod.
