Here’s a list of area restaurants that offer free meals to kids. Leave a comment if you’d like to add a restaurant (or update information).
I recommend calling a venue ahead of time to confirm that their program is still in effect for the day you’d like to dine. I’ve also indicated with an asterisk where we’re not sure if the program is still in place.
Mondays
Lakeside Bar & Grill, 97 Boston Turnpike, Shrewsbury – kids eat free on Monday nights
5 & Diner, 525 Lincoln Street – kids eat free on Monday nights*
Halfway Cafe, 820 Boston Post Road, Marlboro – kids eat free on Monday nights
Tuesdays
Smokestack Urban BBQ, 90 Harding St. (btwn Temple & Winter), Worcester – kids eat free on Tuesdays
Moe’s, 3 Stafford St., Worcester, and 61 Boston Turnpike, Shrewsbury – receive one free kids meal with purchase of adult entrée $5.00 or more
Halfway Cafe, 820 Boston Post Road, Marlboro – kids eat free on Tuesday nights
Uno’s, various locations – kids eat free on Tuesdays in the summer
Wednesdays
JJ’s Sports Bar and Grill, 380 Southwest Cutoff, Northboro – kids eat free with purchase of adult meal
Other
99 Restaurants – kids 10 and under receive a free meal the day after a Red Sox win (with purchase of an adult entrée)
Denny’s, 494 Lincoln Street – kids eat free between 4pm and 10pm.
Nicole, Worcester 
Halfway Cafe is Mon & Tue after 4pm. It’s a little bit of a haul from Worcester but worth the drive every once in a while. Wish they’d open one closer. Love that place! http://www.thehalfwaycafe.com/
Uno’s does Tuesdays. http://www.unos.com/
Not sure if these are still current but 5 & Diner (http://www.lpm5anddiner.com) used to be kids eat free on Mondays. And at one point I know Denny’s (http://www.dennys.com) was every day from 4-10pm.
Kids eat free at Unos Mon-Fri 8/20 – 8/24 & 8/27 – 8/31. Or a $5 off $15 coupon.
http://recp.rm04.net/servlet/MailView?m=4295985&r=NDIwMjczNzIxMgS2&j=MTI5NTcyODQ2S0&mt=1
5 & Diner is now closed down.