A man in Santa Fe had a New Mexico license plate that says IB6UB9 since 2009 according to KOAT “Man fights for controversial license plate back“. It seems to translate to “I will be 6 and you be 9 in a 69 sexual configuration” however the owner says it does not. The state has said it received an unspecified number of complaints that is has no proof of.
Robert Anaya’s vanity license plate was initially approved back in 2009, but he just got a letter from the Motor Vehicle Division saying it’s revoked because it’s considered obscene. The plate in question reads IB6UB9.
“If something is obscene or profanity, we have no place for it in New Mexico,” Taxation and Revenue Department Secretary Demesia Padilla said.
Anaya said his plate is not a sexual reference, but an inside joke with a friend from a night at a casino.
However, the state said it’s gotten enough complaints to cancel the plate. The state can’t provide those complaints because officials say they weren’t written or recorded.
Doesn't Fit In 
The main thing I miss about living in New Hampshire is the license plates–since vanity plates are only about $10 per year, there are a good percentage in the state.
And then there was mine: http://moo.plaidcow.net/2006/12/a_yellow_submrne