I went to a new yoga class last night - it was a 60-minute hot (though only 95 degrees, not 105!) power vinyasa class.
Vinyasa means "flow", so basically you flow from one pose into the next in what is supposed to be graceful movement. I found it harder than regular hot yoga because you have to really know the poses in order to do them in quick succession correctly. Also, there was a lot of arm strength stuff (side plank, lots of pushup position into other poses, etc.) that was challenging for me too.
I think I will like this class a lot once I get the hang of it - I am already sore and it definitely worked a lot of muscles! See the video below for an example of a beginner vinyasa series.