Loooong time ago, I registered a Viagra domain. No website, I just registered it. I was naive about TMs or any of the stuff at that time.
About 3-6 months later I got a Cease and Desist letter from Pfizer legal dept telling me I had to do 3 things...
1. Drop the domain
2. Make sure I have no websites that have the word Viagra in any of the URLs (folders, subdomains, etc)
3. Reply to the letter via fax stating I have done the above and agree to not infringe on their copyright in the future (or something to that affect).
Don't _ _ _ _ with people who have deep pockets. They can literally ruin your life.