Going 150mph on a push bike is not just frightening/skilful. It's physically impossible.
You can read more about the history of motor paced records
here. There's are interesting photos of Jose Meiffret and his ludicrous chainring in
this thread and there's footage of Meiffret on youtube if you look for it. Going further back
Mile-a-minute-Murphy is another interesting character. You could argue that cycling 500+ km from Bordeaux to Paris behind a windbreaker defeats the purpose but Jaques Anquetil and a host of other greats didn't think so. Paul Kimmage gave an account of riding in one of the last ever motorpaced Bordeaux Paris races in his book "Rough Ride".
I know that motorpaced riding isn't very popular these days, outside of the velodrome at least, but it has a long and interesting history.