Compost, I had a friend try to make various baked goods with juicer fiber and they weren't ever tastier because of it. If you're worried about fiber in your diet, I'd suggest eating the fruit instead of juicing it, or incorporating more whole grains in your diet. Hopefully this doesn't come across as overly hostile.

I use some of the fiber from juicing to put in muffins without altering the recipe. The pulp was dry enough to not have to take into account any liquid change. But I never use all the fiber because there is so much of it.

I haven't found any other use though. My attempts in bread itself have not been conclusive. I tried it in soup and it was terrible. It just made the soup gritty.

I found this story about juicing and the leftover pulp:

The Appliance Burmuda Triangle

It might not be helpful, but I found it humorous.

Marni

It makes a good compost and can be added to some baking ingredients for extra bulk.  If it's to wet run it through the juicer a second time.  I always just garbage mine.  Also the if there are any pesticides used on your veggies or fruits it's retained in the pulp and skins. 

Sylvia

i'm using organic veggies. we eat most of them raw or stir-fried w/ olive oil but sometimes like to make fresh juice. i'll try to dehydrate them to see if that works.

we've stopped composting since we had aggressive bees in our compost barrel last summer. had to hire a bee keeper to remove them. i live in phoenix,az & african bees have been found here

thanks, claudia