Try this

[Swass]

Pretty cool, got me every time.

http://digicc.com/fido/

 

[labbats]

I tried 8000 right off, and it didn't work

 

[tcoll777]

767 doesn't work .......

 

[Swass]

If by "it doesn't work" you mean they guess it, you are right. So far this **CENSORED****CENSORED****CENSORED****CENSORED**ed thing has won every time.