As you may or may not be aware, ICANN gave its blessing to the .xxx top-level domain a few months ago which means that before you know it, there are going to be a lot of .xxx domains out there. There will not, however, be a lot of celebrityname.xxx domains out there because a whole bunch of our famous friends have been given protection in the form of permanently reserved domains.
For the moment, details are scarce. Neither the list nor the criteria for protection have been publicized, but through some Whois mumbo-jumbo, it's possible to dig up a partial list. It's worth noting that, for the time being, businesses will have to shell out a few hundred bucks for the same protection, but no one seems to know if these celebrity protections are pro bono or the result of a similar insurance purchase. Either way, .xxx domains, while lucrative, have to potential to cause a lot of people a lot of headaches so any anti-cybersquatting measures are a good idea.
Partial list of protected domains below.