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 absoultely 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.
Hope this link helps you to know more about Gran Canaria :)

canaryislandsinfo.co.uk/gran-canaria/