As a recent PhD entering jobhunt, should I agree to host a weekly seminar? I recently graduated and am temporarily employed as a lecturer at the school I graduated from (9 hours a week of teaching, not counting prep time).  There's a weekly seminar on my field of interest, and I've been asked to take over hosting it.  This would involve handling various logistics like planning the meetings, planning lunches, booking the room, etc. etc.  It would be a lot of work...  On the other hand it might be a neat opportunity to network/make connections/etc., but not that much better than the opportunity one would get just by attending the seminar.

Should I do it or should I save that time for working on my own research/jobhunting?
It's in your interest to focus on research, then job search, then teaching, then service. This is service, so lowest priority. See if you can get a student assistant (grad or undergrad) to do a lot of the grunt work, while you handle the higher level logistical stuff. If you can't get some help, doesn't sound like it's worth your time.