The Villarrica volcano has nice steep slopes for skiing and snowboarding. The view from top is quite amazing. You can see the Andes quite well, plus a lot of the surrounding lakes. Although it's not a big skiing resort, it's worthwhile.
Do not go up if it's too clouded on top of the volcano. You won't see anything once you arrive.
Equipment: Skiing/snowboarding equipment
The Trancura river is divided into 2 parts: the Alto Trancura (upper Trancura) y Bajo Trancura (lower Trancura). The first one is quite fast, with 7 small waterfalls. The latter is rather calm, for a beginner.
Equipment: If you've never done this, and if you're alone, try the Lower Trancura. But if you have done rafting before, or if you've got a group of friends which can actually fill a boat (from 6 to 10), then try the upper Trancura.