The D'agastino's on Addison and Southport has a train going around the dining room, if you go on a Tuesday night they have SmartyPants twisting balloons.
If you are willing to go early for lunch I am a big fan of the Choo Choo in Des Plaines. They deliver your dog or burger on a little train. But after 12:30 pm it gets a little too intense for me, you can feel the nervous anticipation in the air.
If your 6 year-old has the sense of humor that mine has, Hot Doug's would be a totally great place for a party, but again, this would mean day time.
Finally, I like Marie's Pizza Lounge on Lawrence (4129 W Lawrence) it it real retro with vinyl booths and cheesy chandeliers and um, mature waitresses, plus you can watch the guys tossing the dough in the window. But you do have to walk through their adjoining liquor store to get there, which seems to freak some people out.
Oh one final thing, it seems like a few of the Ranalli's are pretty good at the whole indulging the kid thing. I am not a fan of their pizza but they do have a "make your own pizza" option on their menu and my son loved doing a version of this in day camp this summer when they walked over to the Lincoln Park location. I think a big part was wearing the goofy paper hat.
But maybe he actually liked being in charge on the ingredients. But of they can handle a group of 30 day campers, well then they can handle a birthday party no problem.
bjt
"eating is an agricultural act" wendell berry