Gran Canaria is a great place for scuba diving. The subtropical waters mean that you have a good chance of seeing stingrays, octopus, cuttlefish, bream, angel sharks and many other interesting fish.
There are ray banks, reefs and shipwrecks here. There are a number of dive centres on the island. I usually dive with Top Diving – http://www.topdiving.net/en-index.htm who are located in Puerto Escala in Puerto Rico. If you are in Playa del Inglés you can try Sunset Divers – http://www.sunsetdiversgc.com/index.php who also do dive courses and specialist courses.
You can choose from a dive introductions right through to dive courses such as Divemaster or even Instructor courses. The water is usually 20º or 21ºC here so you do need a wetsuit but not a drysuit like you would in the UK!
If you fancy doing something different from mini golf, drinking, sunbathing, fishing and dolphin trips why not give scuba diving a go?