Buy a ticket and join the fans at a game at Sheikh Khalifa International Stadium. If there's nothing scheduled while you're in the area, you might like to check if they offer a tour of the grounds.
You'll have no end of sightseeing choices when in Al Ain. Sheikh Khalifa International Stadium is a great place to begin here, but there are many other worthy places to visit. Al Ain Zoo, Al Ain Mall, and Al Jimi Mall are close to the sporting facility and will fill in your day nicely.