Uh, the expiration of the Assault Weapons Ban is VERY VERY real unlike the tooth fairy or easter bunny.
On the other hand, it's ultimate repeal or expiration IS about as likely as a Godzilla attack as an earlier poster said.
What you are referring to is a sunset provision in the ban...here is a short excerpt about sunset provisions:
"Sunset laws have been promoted by Congress as a means of ending this cycle of statutory debasement. A sunset law is a statute or provision in a law that requires periodic review of the rationale for the continued existence of the particular law, administrative agency, or other governmental function... Most recently, Congress has used sunset provisions in a few narrow contexts. For example, the 1994 Crime Bill's controversial assault-weapons ban sunsets within 10 years. Also, the end of 1995 will mark the sunset of an entire federal agency, the Resolution Trust Corporation (RTC), after six years of existence.
Though sunsetting may appear to be an effective tool for limiting the size of government, in practice sunset provisions have not been very effective, and likely will do little to slow the growth of statutes, agencies, and regulations."
So, although the ban would expire through the inaction of Congress, it is highly unlikely that Congress will let that happen. I read somewhere (I don't know if it is true or not) that Bush and Ashcroft (big surprise from facist Ashcroft) are backing the vote to keep the ban alive.
Certainly nobody has forgotten the ban as the vote to keep it alive is a main topic on a plethora of websites.
Sadly, the ban will probably be around at least as long as you and I.