Rheum - 480+ hours. Shadowed this guy for a whole summer. I didn't know that a few dozen hours of shadowing would suffice, plus he was cool with it.
Cardio - 50 hours. Worked in his office and got to shadow for a few days as well.
IM/EM - 15 hours.
FM/OMM (DO) - 15 hours.
Derm/Mohs Surgeon - 20 hours.
Just started shadowing a cardiologist, about 10 hours in. Even got to watch him put 3 stents in while watching him in the cath lab which was pretty cool.