Four overoptimistic forgerers has been taken by the police in the south russian province Dagestan. One of the men attempted to use a one million us. dollar banknote in a café in the city of Machatjkala. The café owner had of natural reasons difficulties to find change, and got suspicious about the banknotes validity, reports the russian newssite www.narod.ru.
The men had before this attempt, put about 60 000 USD in false banknotes into cirkulation.

Source: swedish newspaper Dagens Nyheter 22/08 2005

LOL @ 1 million USD. Jesus, it's even hard for anyone to believe that a $1k USD exist, (well I mean, a typical obxious person) but 1 million, now that's going a bit too far...

Well, the largest note ever printed was the $100,000 gold certificate, but it never circulated but was used for transfers between federal reserve banks. The largest note to circulate was $10,000 but they have been withdrawn from circulation such that now the largest denomination is $100. Although I did read last year about a clerk that took a gag $200 bill from a person for groceries, and even gave them change. That bill had a picture of President Bush on it and other items in commemoration of 9/11. What I always get a kick out of is all the money the Treasury and Fed have poured into anticounterfeiting features on the new notes, yet everytime I spend a new $20 bill the clerk uses their counterfeit detection pen to see if it's real. They would have saved money by not changing designs and buying everyone an anti-counterfeit pen!

it's somewhat understandable when it happens in a foreign country, although a million-dollar banknote is somewhat of a stretch. it's a bit sad when it happens in our own country, like this old popular story:
http://www.msnbc.msn.com/id/4489683