Title ran too long. What should I show him?
Most of you will think this is lame but the first thing I thought of was All Your Base.
He won’t be interested in stuff like The Straight Dope or Snopes. I’m guessing he already knows about Wikipedia but I’ll mention it to him.
FTR He’s 32, average joe type, stay at home dad/online student.
Google Maps
IMDB
You Tube
Stumbleupon
Tubgirl.
EBay
Amazon
Auto Trader
Edmunds
Tiger Direct
Gutenburg Project on-line books
Google News
Google Earth
His bank/brokerage
ESPN
Sports Illustrated
Orbitz, Expedia, etc…
What are his interests? Sports? Politics? Religion?
how 'bout 2g1c?
::d&r::
S^G
He’s already gone through all the porn? 
Try these.
http://www.worth1000.com/ Photoshop contests.
http://cakewrecks.blogspot.com/ Horrible cakes.
Fark
Slickdeals
Slashdot if he’s nerdy at all
Steve Don’t Eat It
xkcd
Gmail
The Darwin Awards
Galacticast Three years of archived materials. They have nothing new.
Project Gutenberg
Archive.org
Galactic Customs No new stuff. A number of hilarious stories that are a series.
Gotta have some redtube.com [not even remotely safe for work]
http://despair.com/viewall.html
http://www.thinkgeek.com though a 32yo geek would have been there years ago.
Nobody gets away with missing this:
Even if he isn’t interested in Snopes he needs to know about it, and how to use it. Otherwise you will soon find yourself with one more friend you hate seeing in your inbox.
Teach him how to use google. The advanced options, how to limit searches to a domain, how to use the - to remove terms from a search, etc. Especially being a student having strong google skills is a must.
-Otanx
Uncyclopedia
xkcd and other quality webcomics (if that’s to his taste)
Facebook
Newgrounds
Yahoo Games
Lolcats and Failblog
Om nom nom nom
If he’s into entertainment:
Television Without Pity
TV Tropes
I think Google Earth might be the best free thing ever. If he has any hobbies, eBay is a must. Can you imgaine collecting coins or anything like that in the olden days?
Heh, I did. In some ways it sucked but in a lot of ways it was a lot more fun and exciting.
All the ‘obvious ones’ have been said already, except one:
-chan boards
The World Wide Web (WWW) is not the Internet.
Goatse.