Jem Sightings
 
A certainly far-from-complete listing of Jem's unauthorized appearances in the world: 
Treeware
A selection of books and magazines that have some mention of Jem.  This section is still under construction and is by no means complete.  Please also see the International Jem section, as our more literate European Jem fans seem to have gotten a lot more Jem in print than us over here.

Let's Visit a Toy Factory This Non-Fiction book features the making of Jem's Rockin' Roadster!
Cracked Magazine #225, January, 1987. "Barbie Vs. Jem" spoof :)
Dollstars Magazine Spring There is a mysterious mention in issue #2, of "9 dolls in the Jem line, including 2 male figures"  Hmm!
Doll Stars Magazine: Summer, 1986 (said to be "mid June"). Had a contest where you could win 1 of 10 Jem dolls.  Contest ends Sept. 30, 1986. 
Doll Stars Magazine, Fall, 1986 (mid August) Jem's "trumped" feature in Doll Stars.  Here's a page from that feature.
Turmoil in the Toybox, Phil Phillips.  Features a small photo and mention about Jem. An excerpt from the back cover- "This book unmasks the new age, occult, violent, and satanic influences that have invaded the once innocent toy box."  As you may have gathered, it's not exactly pro-Jem :)  And Jem is barely mentioned so save your money... unless you're interested in reading about how satanic the Care Bears are. (I'm not kidding!)
Doll Reader, April & May 1989.  Contains part 1 & 2 respectively of an article written by A. Glenn Mandeville.  While an entertaining read, there are quite a few glaring errors that have confused many newer Jem fans- notably, the mention that a Harvey Gabor doll (among others) was made (!) as well as the incorrect name for Jem's cartoon voice credits.
Contemporary Doll Stars, by A. Glenn Mandeville- contains the reprinted articles from Doll Reader April & May 1989 mentioned above, sadly not in colour as they were in the original articles.  Also several Barbie and other doll articles.
"Forever Barbie" by M.G. Lord; makes mention of Mattel's knee-jerk reaction to create "Barbie & the Rockers" after discovering that Hasbro was planning Jem.
Modern Doll Rarities, by Carla Marie Cross.  Lovely book, but the Jem section is a bit lacking (blurry photos :\ and it doesn't really tell you what the rarest Jem outfits are, just gives you a smattering).  Luckily this one you can find in bargain bins for about $5 at any Chapters (at least here in Canada!) I recommend it for basically everything but the Jem section, though seeing Jem in print is always fun anyway. 
Doll Show Magazine, Issue #1 (summer 2002); Even mentions me! Heehee!  Or so I'm told... I can't find this for sale anywhere! : (

Television/Film
Welcome to the Doll House: Features a character sawing the head off of a Shana or Raya doll.
Offspring: Americana: I'm not sure if there are any Jem dolls on the video, but Rio's head is used on the cover.
Saturday Night Live; The episode with Paris Hilton hosting.  There is a skit about Barbie that mentions Jem.
The O.C.; Episode title: The Ex-Factor; also mentions Jem.
I love the '80's (1985); has a blurb about Jem.  Not that *I* would know any better, but 1985 seems a year early to me...