It depends on the horse, and the current situation, but on average, I don't spend a whole lot of time on the ground. I'm a fan of short and sweet sessions.
If it was a young one, who spent more time on ground then undersaddle, that's different, but for my 15yo who's well finished, I'll mainly just float him around at the trot on line, during that time, really work on his self carriage and frame at the trot and canter. Then I'll work some showmanship at the end just to finesse on that. Pivots, back up, match me, kind of stuff.
If we're someplace new, and he's a little looky, again, I'll just let him float around at the trot as he pleases until I have a consistent ear on me, and he settles.
I do really like Clinton Andersonds ground work. His ground session dvd is probably worth buying.
"You're just as sane as I am."~Luna Lovegood.