Objective: Go into town and pick up Edna's chores.
Reward: The Prep Challenge
Straightforward mission. Do Edna's dirty work: pick up her laundry, buy her groceries, and get her a razor. (For her moustache, perhaps) Ride the bike into town, and approach each of the stores in guerilla-like fashion: Get in and get out.
Checklist of the places to hit:
[ ] Yum Yum Market (Discount meat)
[ ] The Happy Mullet (Edna's Razor)
[ ] Worn In: Used Clothing (Bag of Laundry)
When you've grabbed all three items, hop on the bus for the fastest way back to the Academy