I try to run a late-night room on Friday nights. The wife is usually in bed about 10 or so, and I'll be on til after midnight if I don't have any plans for the next morning. You might want to make sure your GT400 ride is sorted for this week's track; It's been mostly glorified GT400 test sessions lately.
Also, there's the obvious Sunday GT400 racing. My guess is that there will be SOMETHING Sunday afternoon from now on; we're an inertia-happy ground around here.
I would also point out that anytime there are people on, you can put together your own room and just invite everyone in or wait for it to fill with randoms. Random racers tend not to be as clean, in my experience, but depending on class/restrictions, you can get some pretty decent rooms that way. Just stay out of S and U classes.