I checked the FAQ and don't see one mentioned. I love to use RSS to keep up to date on when new questions are posted.
The feed appears on the bottom of the main http://scifi.stackexchange.com page, and should also be picked up by your browser automatically (e.g. in Safari there will be a "RSS" icon on the right of the URL bar that you can click).
The address is feed://scifi.stackexchange.com/feeds
Note that it (like all StackExchange "recent question" feeds) isn't strictly just new questions - whenever a question is edited, it gets added to the feed again (so you'll see duplicates periodically).
For some reason, the "recent questions" feed link does not appear on the recent questions page (i.e. https://scifi.stackexchange.com/questions).
Each user has a "user feed" on their user page, tags have "newest questions" feeds on the tag pages, and individual questions have question feeds (all also located at the bottom on the page and by the browser), if you are interested in finding a more specific feed.
Also at the bottom of every page above the footer on the right is a link to the RSS feed– ZypherMar 9, 2011 at 4:52
@zypher except scifi.stackexchange.com/questions which is where one would second-most expect it. Mar 9, 2011 at 6:02
1The feed also appears in the chat.– user56Mar 9, 2011 at 8:05
@Zypher, @Gilles, I'm not seeing the same feed that Tony Meyer linked anywhere. The only feeds I see are for specific users, specific questions, and starred chat. I'm curious where Tony Meyer got that link, I'd guess he figured it out from the question-specific feed URLs.– user1027Mar 9, 2011 at 23:14
@Keen the almost-footer link that @zypher described is the same? e.g. on scifi.stackexchange.com it's there (it's http://, but that redirects to feed://). Mar 10, 2011 at 2:24
@Tony Meyer, ah I see. I never stay on that page, the lack of avatars weirds me out. :)– user1027Mar 10, 2011 at 4:04