The situps were no big deal, but I have grown to hate burpees. The goal of course is to get them done as quickly as possible every day and it's amazing how much you start to worry about it.
My first goal was to do them continuously without stopping. I was able to do that until day 33. My next goal was do not go over 6 seconds per burpee (on average). I was able to do that until day 67. And my final goal was to never go over 10 minutes for my total time. I was able to do that all the way to the end, just barely. My worst performance was on day 89, which took me 9:51. Day 91 was my next worse at 9:45, and day 99 (100 burpees) was my third, at 9:44.
Below is a plot that shows my time per burpee through the whole challenge.
My technique gradually improved until day 27 or so, then I started to reach my limits for continuous effort. After day 33 I had to start taking rests. I had a few bad days (notably day 73 and 81).
I'm sick of burpees, but glad I stuck it out to the end.