Walk along the beach in either direction. Note that certain stretches become partly flooded on high tide. Your knees will get wet.
Dune-buggy along the coast. Standard 2,5 hour trip for up to 4 people with a driver/guide is R$ 200.
Jangada traditional fishing rafts with sail. R$ 10 per person for about 30 minutes.
Kitesurfing: Canoa kite school (http://www.canoakiteschool.com)
Tandem paragliding on the cliff top. R$ 50 for 15-20 minutes.
A cruise on the river Jaguaribe with a buggy tour before and after and lunch not included in Fortim sets you back R$ 80. Departure 10 AM, return 4 PM.