You could do fun "Derby" slogans such as:
- And they're off!
- Don't scratch! (this is in reference to a no-show, you could do something like, "Don't scratch on the test")
- Something about the In-Field - We're headed to the in-field, See ya at the in-field
For the visual aspect:
- Of course, you could have the students decorate horses and name them (good lesson on adjectives maybe? i.e. Magnificent Melissa)
- They could design Derby Silks
- They design Derby tickets of some sort
Don't know if this helps, but it's what came to my mind
