Not sure if nursery counts, but I work with the Nursery regularly @ our church. Perhaps 10 kids on the nights I work, but I understand the morning attendance is 15-20 or so right now. We don't really have a structured Evening event for the kids, just some romping, sometimes a video/lesson/craft. I'd definitely be open to some suggestions on that or even if it's worth pursuing a more structured night activity for them on Sunday nights. Wednesdays, they do Mission Friends (really junior RA/GA program) and Sunday mornings they have a curriculum, but nothing like KidMo or Hands-On - that's a little our of our $$ range right now.
I know that Children's Church does have some breakout groups, but can't comment more about that right now. I haven't been involved with that yet.
In Him,
-Peter