I really love going out and do some nature tripping so when my friends had a vacation last year on cannary island I didn't waste any opportunity to try climbing Roque Nublo a "must visit" in Gran Canaria may not be that challenging to climb if you are an expert and into extreme sports but the scenery that you can see from this route is absolutely unique. Well I'm the only one in the gang who's on to nature but theirs a lot more to do on Gran Canaria hope this could help. And if you still have some extra time also try visiting Tamadaba national park( about nature again ).
Cheers for the tip! - I don't know much about the Canaries at all really, though have visited briefly a few times on cruise ships.
I've been to all of the major islands. Lanzarote is my favourite. Haven't been back in ages, even though the Canaries are the nearest option for some winter sun.