Actually it's pretty easy: just slip on some mud while walking down the sidewalk.

I sprained my ankle last Wednesday after getting off the bus.  I stepped in some mud (it didn't really look like mud) and I ended up sliding and somehow rolled over my ankle in the process.  The next morning I went to the doctor, they took some x-rays, and they told me nothing was broken but that two out of three ligaments in my right ankle were pulled.  I got an air cast that I need to wear for the next few days. 

Luckily I can walk ok now.  For the first few days, I was hobbling along pretty badly.  I didn't go to work on Thursday and Friday.  I'll be going back today.  Going down stairs is still a little tough (going up stairs is just fine).  In general, my ankle feels extremely weak, but right now there is little pain.  I'm glad things are feeling better but I really need that cast in order to feel like my right foot isn't going to fall off.  Things should be back to normal in a couple of weeks...  just in time for DevConnections.  I hope.