In a 15 min game my opponents time went down to 0 but he was allowed to continue playing until I was timed out.  That certainly doesn’t seem fair.  Any idea what happened?

There’s a weird command called “flag”, and it’s one of the terribly inconvenient things about ICC. If you have autoflag set to off, your opponent can keep playing when his time hits 0 until you type the command “flag”, which flags your opponent. If you don’t want to deal with it, just type
“set autoflag on” into the console.