Advice from GLP Brain Trust on Domain Investing

A few years back, before I knew the term "cybersquatting", I bought a domain name for a sports stadium, before the stadium was built. I guessed about what the future name might be, by combining the name of one of the team's sponsors and the word stadium. Then I forgot about it.

But I searched for it recently, and apparently my guess was on the money. Because the stadium exists now with the sign exactly matching the domain that I own. The website for the stadium is using a different domain with too many words, but mine is a more accurate and more elegant fit.

So, what do I do?

-Can I put it up for sale without getting sued for copyright?

-Should I build a website, and then try to sell it?

-Should I just let it expire worthless?

-Other ideas?

I thought it was like land investing, where you just buy something that you think might go up in value. But now I'm learning that many people think that buying a domain name just for the purpose of selling it later is cybersquatting and is unethical. Is that true? Is that a crappy way to make money?