I would highly suggest not going to the one on 8th and instead going to the one on 148th off of 520 near Crossroads. It's only a mile or two away from that one. I say this due to the fact that I have a group of friends that used to go to the one on 8th and we consistently got bad service and severly rude attitudes from the wait staff. The people at the one on 148th are much more polite and accommodating.
You take the East-bound exit for I-520 from I-405 and then take the first exit (there are two) for 148th Ave and follow it through the light (you can only turn right and once you stop, you're allowed to turn on a red there from either lane), then go through the next stoplight and Denny's is immediately on the right.
2233 148th Ave NE
Bellevue, WA 98007
I will be there around 3-4am Saturday evening/Sunday morning, as I almost always am after I go to the geeky LARP I attend.