EK used to allow stopovers in Dubai free of charge. It might be worth calling them to see if this is still the case.

As others have mentioned, in order to do something within your timeframe, traffic will have to work in your favor. This is rarely a good idea in Dubai. Explore the airport-there is plenty to keep you busy for a few hours.

If you are flying in C or F class, just relax in the lounge.