I don't know of any that are exactly like spamgourmet. I think it's the best
(bias alert...)
There's
http://sneakemail.com which has addresses that don't automatically expire -- they've been around for a few months longer than we have
A couple with date-expiring addresses are
http://jetable.org and
http://mailexpire.com (mailexpire was around ages ago, but then went away and came back).
More recently there are the "mail drop" types, that require no signup at all, but you have to go to their websites to read the messages, like
http://mailinator.com and
http://dodgeit.com
Disclaimer -- it's probably unfair to sum up those services the way I just did -- they likely all have additional features worth checking out. People often sum up spamgourmet in a sentence or two -- it's irritating and often misleading, but I suppose they have to do it.
There are certainly others -- some commercial. Do a web search and you'll see.
If you want truly anonymous email, search for "anonymous remailer" -- I don't know much about those, or even if they're still around.