surprises that challenge you

Isn't this always the case: a surprise work out challenges your body in new unexpected ways. On Friday afternoon I went to the gym and started off with the usual: cycling, abs, and then treadmill uphill walk. About 20min into my uphill walk, a fellow spin enthusiast came to me and told me that a spin instructor was about to start a 45min spin class off-schedule. I happily changed course and went to the surprise spin class, which was refreshingly free-ride. Afterwards I lifted free weights for 15min and then hopped on the treadmill for 2km uphill walk and 4km run, inclination 1, speed 10.3-10.5km/hr. In the sauna I fell asleep!
On Saturday morning I went for a very long run: 2hrs:50min, about 25.5-26.5km. I thoroughly enjoyed it! In the afternoon I went to the gym for 1hr cycling, 1hr treadmill uphill walk, 15min team work out abs and 30min weight lifting. 15min sauna... before going to the movies!
On Sunday morning I felt like I could use some sleep, but discipline prevailed and I ran 1hr:45min, about 17km. In the afternoon yet another surprise was expecting me: I started off with 30min cycling and 1hr treadmill uphill walk; but then I went to the body step class. 55min cardio stepping up and down the step... total calf burner! After class I lifted weights and did abs for 30min, then finished off with 15min cycling. The sauna was a relief!
This morning I braved the winds (and the occasional showers in the darkness) and hit the dunes for a super early 2hr-long run of 18.5km. My legs were dead from yesterday's body step class! I came home just in time for my appointment with the carpenter. This afternoon I will definitely do the 2hr spin class that starts off at 18:30. Before this, maybe cycling/treadmill?