Oita

Hiking:

Mt. Kuju and Yufuin - are amazing places, especially if you like nature and hiking. Yufuin is a small, quaint little area, very historical, with beautiful rivers, onsen, and cold springs as well.

Beppu

Beppu Sand Onsen - on the beach and different from your typical onsen. It's outdoor and they cover you in sand that's heated from underground. It's nice because you can hear the ocean, but it can get a little too hot for buried in the sand. It's around ￥1,000 per person.

The mud onsen in Beppu is fun. The outdoor onsen is mixed, but the men and women are separated by a wooden pole down the middle of the bath. In case you're hesitant about mixed bathing, the water is so cloudy (from the mud) that you can't see any part of your body that's in the water.

eating:

There was also a really good Jamaican restaurant in Beppu called Big Bamboo's - you can find directions on Google.