That old nemesis that makes everyone go to work and hour early is rapidly 
approaching.  Just for grins, I tried this. I'm running Windows 2000 and 
have my clock set to automatically adjust for DST.

t=Time.local(2001, 4, 1, 2,0)
puts t

and saw this.

Sun Apr 01 01:00:00 Eastern Standard Time 2001

This can't be right.  It's 03:00 EDT (local time).    02:00 EDT(local time) 
doesn't exist by definition.

Having seen this I tried this.

t=Time.local(2001,10,7,1,59,59)

and saw this

Sun Oct 07 02:59:59 Eastern Daylight Time 2001

Now we know that there are two 01:59:59 seconds on the day we get that hour 
back.  But neither one of them is the time Ruby reports. In fact the time 
Ruby reports for Oct 7, 2001 doesn't exist by definition.

I also tried this on an NT 4.0 box and had the same experience.