crockpot brownies/molten cake...

then just bring some vanilla ice cream with you- and you're money.

I've heard of cheesecake made in a crock pot. I vaguely recall it being on Food Network somewhere...

or some kind of fruit butter: apple/pumpkin/plum butter can all be made in a slow cooker & spooned over ice cream

Rice pudding would be a fail-safe crockpot pudding. Could even serve with jam previously made in the crock pot.

I haven't tried it yet but Jessica from how sweet it is just posted this incredible looking crockpot dessert: http://www.howsweeteats.com/2011/10/crockpot-caramel-apple-crumble/. Yum!

Great idea for a party theme. Here is a roundup of 40 different desserts and candy recipes all made using crock pots or slow cookers...http://www.bystephanielynn.com/2011/10/40-crock-pot-slow-cooker-dessert-candy.html - it may help with some inspiration for your dish. Have a great party!

http://stephanieodea.com/
this woman does everything in a slow cooker. you can look on her site. also, sandra lee from food network makes stuff in her slow cooker. ive never made it but i saw her make a spoon cake in hers and it looked delish!
http://www.foodnetwork.com/recipes/sandra-lee/heirloom-carrot-spoon-cake-recipe/index.html

http://southernfood.about.com/od/crockpotdessertrecipes/r/bl102c2.htm
this looks just like a pumpkin pudding recipe that I make every year for thanksgiving. It's the only reason I ever buy "biscuit mix." It's really delicious.

What about just slow-cooked apples and pears sweetened and spiced and then served with some heavy cream?

You could also try making Norwegian fruit soup. I just made some today, but on the stovetop. My mom's recipe is 4 cups of dried fruit (she uses 2 cups raisins, 1 cup prunes, 1 cup apricots) with 8 cups water plus 3 tablespoons tapioca pearls, 1/4 cup sugar, and a cinnamon stick. You could also replace some of the water with cider or orange juice. It needs to thicken and the tapioca needs to cook through (especially if it's not the quick-cook kind), so it would be ideal for cooking on low all day or on high for several hours. Serve it with a little half 'n' half and you're done. So good. But very rich, so recommend small servings. :)

Chocolate pudding cake...it's fabulous!

http://vegetarian.about.com/od/vegetariancrockpotrecipe/r/choccrockpot1.htm

You probably don't have a steamed-pudding mold that fits your crock pot, but if you did, you could make a steamed pudding. It has the added advantage of being really easy to transport--just carry it in its mold.

I make this recipe every Thanksgiving. Either my family is REALLY polite, or it's yummy:

Steamed Pumpkin Pudding
1 3/4 c. sifted flour
1 t. baking powder
1/2 t.each: salt,baking soda,cinnamon,ginger,cloves, grains of paradise (g.o.p. is optional but yummy)
1/2 c. shortening or butter
1 c. brown sugar, packed
2 eggs
1/3 c. buttermilk
1/2 c. cooked or canned pumpkin
If you like, you can add bunch of chopped walnuts or pecans and/or raisins and/or cranberries (dried or fresh) and/or chopped crystallized ginger
Sift flour, baking powder, salt, soda and spices together. Cream shortening and sugar. Add eggs and beat well. Add flour mixture alternately with buttermilk and pumpkin. Pour into greased 1 1/2 qt. mold. Seal and steam 1 3/4 hr. or until toothpick stuck in center comes out clean. (Go ahead and steam the heck out of it. You can't really overcook it.) Cool a few minutes, loosen from sides of mold, remove from mold, serve warm with Hard Sauce.

Cheesecake. Use your regular recipe in a springform that fits in the cooker. Put a ring of foil at the bottom to elevate the pan. Cover the WHOLE pan in foil, very important. Place a couple of dish towels o er the top to absorb extra moisture, so you do t have soggy crust. Then place on the cover and let cook for 6 hours. Perfect cheesecake!!

My family really loves rice pudding in the crockpot. Here's my recipe:
http://dumbsainthood.wordpress.com/2011/01/22/a-bit-of-meme-and-a-bit-about-rice-pudding/

I have made this numerous times. It is easy and very yummy Slow Cooked Winter Bread Pudding with Dried Pears http://www.foodnetwork.com/recipes/food-network-kitchens/slow-cooked-winter-bread-pudding-with-dried-pears-recipe/index.html