I have created a wp7 game which is "inspired" by the flash game Curveball. I have it released under a different name, but I would like to use the name Curveball for my app as well. There are copies of the flash game everywhere, and there are references to PDMedia.net as the author, but I am unable to find any more information on the author. There is no game related Trademark for the name Curveball, but I don't know if the TESS site is the only or even best place to look for those things. I don't think it's worth paying for legal advice at this point, just trying to get a feel for my legal options regarding using that name.

In case of doubt, better avoid using the name in the first place.

Also jeez, you were right it's hard to find information about the author. The site is dead and there doesn't seem any information on the net about them. So, I looked on the web archive. Ugh, site is old, I swear. Here's one working back-up I found, maybe there are some newer ones but this one seems to have Curve Ball in it already and has some relevant information:
http://web.archive.org/web/20020527102837/http://www.pdmedia.net/

The company was called Paragon Digital Media. The "PDM people" section mentions who was the staff of the company (or at least the key staff). Maybe this helps.

Thanks for the link. The curveball game is hosted on hundreds if not thousands of websites and it seems to be very popular even though it's abandoned.