I believe the record at this point is something like 760. But he's not a guest, so he doesn't count.
I know of one person who says he's been on it like 170 times, and then I KNOW of one person who's broken 100. Then there's one guy I've seen on quite a few separate days, and he rides multiple times per day, so he's got to be up there as well. I'm sure there're quite a few past 100 by now.
Myself, I'm at 37, hopefully to 100 by the time I leave in May.