I have been branded with a bland sense of humor primarily because of the fact that I don't ridicule people for humor. This is something that many NT's do regularly, and seem to shrug it off. I don't find much humor in putting someone down, and don't like someone doing it to me. Like Mysteriously absent, I too have a hard time reading people when they attempt to be funny by being serious about something. Oddly enough, this is one of the few areas of humor I am good at, and i believe it's becasue I tend to send out mixed signals and body language anyways, so people I'm communicating with can't tell if I'm serious or not.
Instead, I find situational humor much more amusing. For instance, I was laughing insanely about a news story where a chicken truck hauling live chickens wrecked on the interstate. Chickens were running everywhere, and the police were chasing them around the road trying to gather them up. Some of my NT friends were barely only mildly amused