I'd do #1 that mecabq recommends above, if you're feeling lucky.

But just to stretch your legs, it might be 'interesting' to take a quick taxi to Deira City Centre to see a typical Middle Eastern past-time (i.e. walking around a shopping mall) because it's quite close to the airport. Or take a taxi to the Irish Village (also very close to the airport), for a pint of guinness in the sunshine. It's quite a nice setting, and less than 5 mins by taxi.