Merely by viewing source on spam email, we get a great chance to see how they slip by filters:
Thi<!--5928-->s is NO<!--1340-->T SPA<!--8609-->M - Yo<!--32716-->u ha<!--25550-->ve recei<!--1443-->ved th<!--22664-->is e-ma<!--29932-->il beca<!--28334-->use at o<!--4226-->ne tim<!--19880-->e or ano<!--21548-->ther yo<!--31117-->u ente<!--7010-->red t<!--17096-->he week<!--24332-->ly dr<!--225-->aw at one of ou<!--7043-->r po<!--17546-->rtals or F<!--6560-->FA sit<!--13829-->es.
Which renders as:
This is NOT SPAM - You have received this e-mail because at one time or another you entered the weekly draw at one of our portals or FFA sites.
I'm more or less resigned to getting spam, but it would be nice if they weren't lying about it (the spam goes on to cite "Bill s. 1618 TITLE III" as proof that it's not spam, but that bill died in committee).
The stuff that frosts my cake now is the gibberish spam that embeds a single tag to pull in the real spam.