Purchase tickets to watch a game at Tampereen Jaahali. If there's nothing happening while you're there, you might like to check if the stadium offers a guided tour of the grounds.
You'll be spoiled for sightseeing choice when visiting Tampere. Tampereen Jaahali is a great place to begin here, but there are lots of other worthwhile spots to experience. Sarkanniemi, Kaleva Church, and Tampere Cathedral are near the sporting facility and will round out your day nicely.