I'd forgotten the racetrack was a challenge. I always have it out, it gives OK drops. I pulled the two petting zoos and the stargazers ridge (and the orphanage) back out of storage to give them a chance but so far I get very little return. Same with Lorelei's fountain - I've never gotten anything more than one water or one mermaid scale ( and the occasional fish) off of it even at the height of the troll hunter's challenges. Nothing. I'm glad I got the table which I like off the same challenge because the fountain is a total bust for me.