Two Hours Spinning is Hard Work

I went to the Gym's two hour spinning session today (they do this one Sunday a month during the Winter) and it's the first time I've been. Despite my approach of taking a little easier than my normal Spinning classes (45-60 minutes duration) I still found my legs dying on me as I reached the last 15! Afternoon on the sofa beckons (as it was yesterday but that was alcohol related!).