For my son's 5th birthday party we did a cowboy theme. Whe had the party at a local park (Orlando Wetlands Park) with no playground, and pleanty of open space. I find that the kids don't pay attention as well with a playground in sight.  When the kids arrived we gave them a hat, blue or red bandanna, self adhesive moustache, and a sherriff's badge with their name on it (to also serve as their name tag). The party started at high noon, so we served hotdogs, beans, chips, and juice and water first. I made napkin holsters out of brown paper, using a plastic holster as a template, trace and cut out.  Lace it up with twine.  I ordered bandanna print napkins online and put a red plastic fork and spoon in it. The kids picked a little and went straight for the lassos I had made.  I made a steer head out of plywood and painted it, screwed two stakes to the bottom and stuck it into a hay bale ($5 at Tractor Supply Store or Farm and Feed Store). I set up another haybale with a saddle (borrowed) on it so the kids could sit on the saddle and rope the steer. We took a picture of the kids on the saddle. The dads and kids had a ball lassoing eachother, and being lassoed.  The rope was cheap at Lowe's or Home Depot.  I used a cowbell I ordered online to get the kids attention. We hired a horse and wagon ride to come and take the kids on a ride. The wagon was beautiful and fit our cowboy theme perfectly.  It took half the kids while the other half stayed and played games.  I set up pin the moustache on the cowboy.  The cowboy was made out of cardboard and drawn on.  The moustaches were from Oriental Trading Company. The kids pulled their bandanna over their eyes.  The next game was Toss the Snake into the Hat.  For the next game I took some left over rope and made it into a "snake". The kids lined up while I moved it along the ground, they had to jump over the "snake".  For the next game I used a kiddie pool, filled it with rocks I had previously painted gold, and two bags of playground sand the kids had to goldmine and find as many gold nuggets as they could in 60 seconds. Next, I made a knock down the bad guy game out of scrap wood and hinges I bought at the hardware store.  My son painted one of the badguy faces (he was very proud of it). When the wagon ride came back, we put the kids who had done the games to go on the ride, and vice versa. After those kids finished the ride, we did the horse pinata I ordered online.  I filled it with old fashioned candy, fireballs, redhots, lemon heads, flavored sticks (like candycanes, but different flavors and no bend), and wax bottles. Next we did the cake.  I ordered a horseshoe cake pan and horse cake topper from Birthday Party Express. I shredded the large non-frosted shredded wheat for "hay" around the cake. I used my cowbell to call them over to the steer head and saddle roping area and took a picture of all the kids. I edited it on the computer and made the color sepia and printed one out to send with the thankyou cards. Then we opened presents and gave out the goodie bags.  The kids got to keep a lasso, the hat, bandanna, and sheriff star, the gold nuggets, patriotic tattoos, plastic snakes, I made chocolate oatmeal cookies (they looked like cow paddies) in a clear bag and attached a computer generated tag "Made with love on the xxx Ranch with a picture of a cow on them and did a similar thing with rattlesnake eggs, but I could not find the white peanut m&ms, I used marshmellows and a tag that read Caution: Rattlesnake eggs Right likely to hatch at any moment (both cookie and egg ideas I got from this website).  The several parents told me their kids had a great time and are still playing with the lasso.