I've had two rolling bee encounters this summer. One was a couple months ago, bee flew in my helmet. I couldn't get it off in time to prevent being stung (having a shaved head probably doesn't help any in that respect).

2nd time was last Wednesday. The little bugger somehow got himself lodged between my glasses and the side of my head and stung me right on the temple before I could yank the glasses off. That one was slightly sore and itchy for three days. There's still a slight red mark visible.