If you come into contact with a $50 or $100 bill, check it carefully! The Secret Service says there's a lot more funny money floating around the NYC-metro area.
WNBC has PDFS explaining what to look for on the bills ($50, $100); it's pretty to cool to see the differences. Since the Secret Service is pointing out printing differences, it looks like the paper is pretty close and has that metal strand.
We've been stuck with counterfeit money twice - $5 bill both times which savvy cashiers marked with the special pen - and it sucks worse than being stuck with Canadian currency. And here's the Secret Service on how to know your money.
Back in 1996, some people working in the printing office at Columbia University were busted for printing $80,000 in $20 bills - they had used similar paper and color copiers to create "fair copies."