Church Activities for Children...

Our church does an annual "Pumpkin Patch" every Halloween in the church gym so the neighborhood kids have a safe alternative to trick or treating - we have a lot of homemade arcade-type games (ring toss, beanbag toss, etc.), simple hot dog dinner and pumpkin pie dessert, and of course way too much candy.

We've also done church/neighborhood bbq's with music and a couple rented bounce houses for the kids.

Another neighborhood church where my kids attend a midweek kids club has "friends day carnivals" 2x a year where the kids are encouraged to bring a friend, and for fun they'll set a goal for X number of total guests and if the goal is met, the youth minister gets a cream pie in the face ;-).

My church normally does a cook out for the kids before going back to school. We have done it several different ways. If it's too hot to be outside, we set our gym up like a carnaval theme. There are different games set up like bean bag toss, ring toss, basketball shots and sometimes face painting. We have tables set up for word games. We give out little prizes for those that win.

Even if you are outside, you can still set up the carnaval theme. Playing kickball and dodge ball are games that the kids enjoyed, even the adults.

We actually did a mini-carnaval one year in our parking lot. It was open to the community. We did the popcorn, cotton candy and dunking booth. We had tables set up for people to turn in their tickets and get prizes. We hung the stuffed animals up just like a real carnaval. That was a blast. The entire neighborhood enjoyed the carnaval.

We also give out supply bags at the "Back to school cookouts".

As for planning extra activities to promote your ministry, involve the kids in skits and plays that are geared towards your ministry. That is something we do as well. I teach Sunday School at my church. My age group is 5-8. They are so amazing when it comes to doing skits or plays.

Does the convention that your church is associated with have a website? Ours (Southern Baptist) has a great one with all sorts of ideas and resources.
You might also want to go browse at the local Christian Bookstore...they should have lots of resources and ideas.
It is difficult to give you much specific advice without knowing how large a church you are involved with, how much adult help you can count on and how many children you are going to be dealing with

good idea! my church does these activity days about once every quarter and my kids love them. i think it gives kids a chance to play and make friends with the group of people that they may not otherwise get much of a chance to do that with during worship services. typically our church does games like bean bag toss, bowling (little plastic ball and pins), duck duck goose, balloon toss, races, kid's size basketball hoop, etc. they always have a snack-- popcorn, raisins, decorate their own cookies. they make a simple craft. once we were asked to send a family photo with the kids and they glued the photo onto the front of a shiny cardboard star. it hangs in my kids' room and they love it. if it is close to mother's day, father's day, or Christmas the craft is often something they can give as a gift to a parent. sometimes there is a theme, but sometimes it's just a game and treat day. here in Utah, Pioneer Day is a state holiday so we have done pioneer themed activities like making soap, churning butter, making spinny toys out of rope and a circle of wood, dipping candles. that is one of my son's favorite activity days. carnival themed activities can be really fun too, if you have enough adults or teens to help you with every station. so many possibilities!

We have quarterly activities days at church and church members homes. We have had Trunk or Treat parties, the parents back up to the sidewalk around the church and give out candy sitting in their trunks or from the back of their vans, we have Christmas parties with Santa and some without him, there have been pizza parties, cookie decorating parties, parades in the parking lot of the Church, all kinds of things like that.

I used to go to the LDS church where kids activities are really awesome so I have added a quote below.

This is a direct quote from the lds.org website about primary programs.
"Primary activity days give children opportunities to interact with each other and have wholesome fun by participating in physical, creative, cultural, and service activities. They give children the opportunity to put into action the principles they have been taught during Sunday Primary and in their homes."

N., you have been called to a awesome position and have a huge task in teaching these children to love God and to teach them that they are loved by Him.

Here are the links I found that look good:
http://www.childrens-church-ministry.com/
http://www.childrenschurchgames.com/
http://ministry-to-children.com/

I just googled church primary activities for little kids.

Our church recently did a family day that was geared toward children with an old world (Bible time) market. They had a mosaic art station, some authentic treats, design a wooden necklace, metal tooling, foot races for the kids, and they had a bunch of costumes from old plays etc.at the front entrance so everyone could get dressed-up as they came it. It was a lot of fun and appealed to a wide age range.
Good luck, I know children's ministry can be a LABOR of love!