The reason...

...why my arm is hurting like crazy, and why my colleagues are having dinner without me...

I played partyplanner for my colleagues, the plan was to go bowling and have dinner afterwards. All very nice, but yesterdays experiment was badly designed, so after we finished bowling today I had to leave to take samples.
Only good thing is that I had a few beers at the bowling alley, and that makes the pain in my arm go away :) yay for beer! It also makes sampling a little more complicated and adventurous. I think it went perfect ;)