Okay, here's what I found...
Topsfield Fair...runs from 10/3-10/13, 10a-10p. ( Jeff Corwin will be there on the 11th.$14 to see him). Tickets are $12 at the gate, $8 prepurchased. Ride Tickets are 11/$19. Parking is $8. Children under 8 get in free.
The Big E (Springfield) runs from 9/12-9/28. Advance Tickets are $10, parking is $10. Don't know how much the rides are...probably very expensive on a weekend.
King Richard's Faire (Carver) is every weekend from 8/30-10/19. Tickets online are $23.50, at gate $25.00, group tix for 25 or more adults are $21 apiece. There is a $1 off coupon online for gate admission. Be aware, some of the shows can be a little risque...for instance, 9/13 is a Cleavage Contest, and 10/4 is Tattoo Day...but 9/27 is Prince and Princess Costume Day, for the 12 and younger set.
Cranberry Festival is 10/11. Good for very young children, boring for everyone else...besides, OKW Lover can't make this one.
Does anyone think a whale watch might be fun? Of course, it's weather-dependent, and you have to be able to take some rough seas sometimes, but it's a blast. Adult cost $37, children $25 (If we get more than 20, it drops to $30 and $20, respectively). Goes from noon to about 4pm.
Any other ideas? Suggestions?