Maybe not an adventure, but you can do some fun things.
- Culebra has amazing beaches
- Visit the bioluminescent bay
- Visit El Yunque. You can do the regular tour or visit other trails.
- You can go rapeling
- You can go SCUBA diving
- You can go visit reefs
- You can go zip-lining
They're not limited to PR, but you can do them someplace new/different.
You can escape the cold. (45° here and raining. I _kind_ of wish I was back in PR)