Relaxing place to go, been to Playa Blanca loads of times - You can get really nice villas for not much cash.
Do hire a car and have a scoot round the Island, take a look at the interesting little villages.
Have lunch at El Golfo
Visit the far north, take in the views from Mirador Del Rio, and visit La Graciosa.
Have a picnic on the beach at Famara.
Can let you know loads if you're in Playa Blanca, much less if you're in one of the other resorts.