Depends on where you are :
- in Cleveland Heights, I was given a ticket for doing 36 in a 35. Same cops that gave a buddy of mine a $175 ticket for breaking a small branch off a tree (destruction of public property). Got the ticket thrown out in court for the 36.
- in Downtown Cleveland from 3AM to 6AM, it's the wild west; if you can keep your car steady at 100mph on side streets, you won't get a ticket. Just watch out for the paper trucks, because stop signs and red lights do not apply to them in this time period.
Everywhere else it's pretty much 5mph over, but on the freeways I've seen people doing 70 in the 60mph and cops just sit there.