Once you navigate through the subways one in Fallout 3, then you can just fast travel it. It did take me a few tries to get where I wanted to go in that area early on, though.
I finally finished up Half Life 2, Episode I. I think between the last time I played it and today, they added achievements... so I have the last three game progress achievements and nothing else! D'oh.
I'll probably start on Episode 2 pretty soon.