Ask HN: Where to find people with (small) project ideas?

I love programming. And I love programming more if my program is helping other people.

So my simple question is: Where can I find people who are looking for a programmer to realise their idea? I don't want to get paid.

I tried to make an "selling" offer on Fiverr for $0 but Fiverr requires me to ask for at least $5.