I bet you're one of those goofs trying to show off you know Latin plurals and then use words like stadia with the gratingly incorrect plural suffixes in the ablative, nominative, etc. cases. With your serious face on, expecting to play the foreign plural game in English, how would you say "We gave three stadia's old seats our new line of blue upholstery"? We're communicating in English, not Latin. If you are, use the proper suffix at all times.