Invitations
Make a false front for your party invitation with the picture of an outhouse. Open the door to get the party information. You’re invited to an extreme party….Extremely gross party!

Cakes
Anything chocolate, especially a chocolate roll-up log cake

Round cake decorated as a moon

Kitty Litter Cake

Decorations
Use brown and yellow balloons, plates and napkins. 

You could even use a yellow rubber ducky theme with this party. You know, it's bathing, something you might want to do after this party, if you think about it too much.

Put up toilet paper like you would usually use streamers. The really cheap 1-ply toilet paper might not break too easily and will string up easier.

Make a cow pie centerpiece. Spray foam in a circle on a Styrofoam plate and stick in a few bits of hay. After it dries, paint it brown.

Hang up crescent moons for your outhouse party.

Costumes/Dress up
Toilet paper. Just wrap up in toilet paper, or stick it to the bottom of your shoes.

You can also make folded newspaper hats. You can guess why newspapers might be party of an outhouse party.

Games and Activities
Potty Songs (ages 3-16)
Invite the guests to share any songs they know about going potty. Then everyone try to sing them. They’re usually quite simple and, sometimes unfortunately, unforgettable. I learned one from a roommate in college that had the words: I have to pee so bad it hurts, it hurts. I’m going to pee in streams and not in squirts. If I don’t find a bathroom soon I’m going to fill this whole darn room. I have to pee so bad it hurts, it hurts. It’s kind of strange but fun when the whole group gets going with it.

Outhouse Surprise (ages 3-16)
Guess the surprise found in the outhouse. Okay, you didn’t really find it in an outhouse. But this is probably the best outhouse party game I’ve got. Put the following items in individual bags and number the bags. You can use plastic bags inside brown paper bags if you want. Have everyone pass the bags around, feeling but not looking, and guessing what’s really inside, then writing it down on their paper. Use some of these items: peeled grapes, cooked spaghetti lightly coated with oil, cooked meatballs, malt balls, keys, coins, lip balm, raisins, and prunes. If you coat a few of the items with a bit of oil it adds to the EWW factor. You may need to have napkins or moist towlettes available for everyone during and after this game.

Toilette Fashion (ages 3-16)
Dress with toilet paper. Divide your guests into teams and have them dress one of their teammates with toilet paper. Who can design the best outfit You might see the same thing at an outhouse party as you would see coming out of an outhouse. 

Surprise! (ages 5-16)
Melt candy bars in a folded napkin and have everyone guess which candy bar it is. Try Tootsie Rolls and anything with chocolate in it. Put the candy bar and napkin in the microwave for about 30 seconds on high. Number the napkins and write down what they are so you’ll remember after the party starts.

I Gotta Go! (ages 5-16)
Instruct all the guests to keep their legs crossed when sitting down. Anyone caught uncrossing their legs, has to sit on the throne – an upside down bucket with a toilet seat on it. They can be dethroned when someone else is caught with uncrossed legs. 

Outhouse Relay Race (ages 6-16)
Race to take a dump to the outhouse. Split the guests into two teams. Have them fill a cup with water (add yellow food coloring), run to an outhouse (a large cardboard box) go inside and dump the water in a bucket, then come back to the waiting line for the next guest in line to go.

Musical Arm Farts (ages 6-16)
I can’t do this one, but my kids think it’s great. Allow your guests to take turns trying to impress each other with the loudest and most obnoxious arm farts they can make. If you don’t know how to do it, don’t ask me. Somehow you put your hand in your armpit and squish it down and the arm going through makes a noise similar to passing gas. You'll hear the same things at an outhouse party as you might hear coming from an outhouse.

Toilet Scramble (ages 8-16)
Unscramble the outhouse oriented words. Don’t worry, there’s nothing obscene.

Crafts
Build a Cracker Outhouse (ages 3-12)
Build outhouses with sugar cubes and frosting or use graham crackers and frosting. Give each guest a paper plate to build it on. White frosting looks good for the building. But, make sure you provide chocolate frosting, because, um, it could be used to look like, um, yucky stuff. 

Miniature Outhouse (ages 7-16)
Make your own miniature outhouse. Either use cardstock to build and outhouse with four walls, door and a roof or use pre-cut wood. Inside, use an upside down thimble, wooden spool or a small upside down terra cotta planter for the seat. Glue a little dolly on the seat to complete the look.

Droppings of various sizes – malt balls, chocolate covered raisins, etc.

Cupcakes with mounds of chocolate frosting, piped like, well, some of that stuff you might find in an outhouse.

Cow pies – Make individual pies. Bake small pie crusts in cupcake tins and fill with chocolate pudding, chocolate cookie crumbs and whipped cream.

Chocolate Turds – Pipe chocolate meringues as a pile of turds and bake.

Beans