I'm of the opinion that it is generally not possible to "cram" for interviews.
I'd tend to agree, yet when faced with an opportunity like this I can't help but scramble to find some way to improve my chances, even if the way is of questionable value. It would feel wrong to just sit back and accept whatever happens. Part of the difficulty does come from having no real clue exactly what they'll have me doing. It's client systems (things like community software - think Steam) instead of actual games, I'm pretty sure.
Either way, I am a decent programmer (or at least, so I tell myself) and won't be going into this completely blind to the skills and knowledge required. I was just hoping to brush up on some of the more pertinent topics.