Collect the Whole Set

I just got my Global Village Habitat T-shirt. Woo Hoo!

So far we have several white ones from previous builds here in Winnipeg, a red one from Darryl's adventure as team leader this year and now, a green one.

Blue is usually for the homeowners so we won't be getting one of those, but there's still yellow, orange, purple, pink etc. I wonder what we'd have to do to add those to our collection?

After all, it's really all about the T-shirts!