You'll laugh, you'll cry (not necessarily in that order)
My friend David Shenk, author of the indispensable Alzheimer's book The Forgetting, has directed four short animated films about the disease. Depressing, but the most straightforward, easily-grasped explanation you're ever likely to find.
For lighter fare, my friend Rob Nassau (by the way, these are real friends, not Internet friends) edited the hilarious web soap opera Horrible People. Here's the trailer.