What set of interesting web sites would be complete without mentioning Ebay? You can browse the auctions and even use their help system without registering. (Bidding and sending suggestions, however, are another matter.) And since they bought Paypal, paying for an auction is easier than ever. You will sometimes run across an auction in a foreign currency (at least I have) so you might want to check out the exchange rates at Xe or Exchangerate.com. If you aren't into auctions, Ebay also bought the shopping site Half.com. And, if you absolutely MUST have Ebay branded items, then Ebay-o-rama is the place for you.
If shopping is your thing, you can find lots of different things to buy at Amazon.com.
The last two times I read reviews of search engines, Google got one of the highest ratings. I know I like it. They also have their own store. If by some strange happenstance Google isn't working, you could try the AltaVista search engine or the search at Yahoo!.
Webrings used to be cool, but ever since Yahoo! bought them out, they don't always work right. I wonder if they ever will again ...
If you like to watch the northern lights and want to know when they might occur again, there's a forecast at spaceweather.com, along with past pictures and other neat sky information. You can also check out the Aurora cam at SPACE.com and the forecast map from the University of Alaska Geophysical Institute.
If you want to know where your money has been and where it goes after you spend it, you should give Where's George? a try. For more information, check the directory of Where's George related pages. Then again, if you're going to be in Canada, you could try the Canadian version, Where's Willy?.
If you want to see past versions of websites (possibly including your own), go to the Internet Wayback Machine site (you'll need to know the URL - searching is not yet an option).
Where else would you go for news of the weird but the News of the Weird website?
For pictures of people at certain times of the day, check out Human Clock. You can even submit your own pictures (be sure to read the requirements first).
Who would have guessed there were web pages devoted to the mysterious words xyzzy and plugh? (Not counting the Jargon File's xyzzy and plugh pages, of course.)
If you think someone sent you a rot13 message, you can try the conversion pages at rot13.com or Soft Rock Software.