In my Calculus class today I showed just a short clip from this video (“the limit does not exist!”).
Apparently, completely and totally without my knowledge, I showed this video today, on October 3rd, which just happens to be Mean Girls Day. So..happy Mean Girls Day! (happy/mean…that sounds a little funny)
Kudos to the folks who put these videos together!
Random Walks 
A thorough discussion of the limit problem in Mean Girls can be found here (thanks, Matthew Wright, for pointing this out to me!):
http://kasmana.people.cofc.edu/MATHFICT/mfview.php?callnumber=mf450