Lets see...
5 hours a week of game time
5 hours a week of game prep
10 hours a week on game related forums (including one I run for my group)
10 hours a week working on one of my two homebrews
That is about 30 hours. It was a great deal more (time spent making player handouts, new character sheets, and so forth) but I've cut it back a bit since I started playing Star Wars Galaxies: An Empire Divided. Now if we want to count SWG as "role playing" (which it sorta is) that would be another 4 hours a night through the week and maybe 12 hours on the weekend, or 32 more hours.
I sleep 4 hours a day through the week, 10 on the weekend.