Zynga have been cross-promoting in their games like crazy, and tonight there is a new mission available in FrontierVille that rewards players with an adorable mule for their FarmVille farm when completed. Titled, "The FarmVille Quest I", this mission is awfully easy one to complete. All you need to do is plant 20 crops, harvest 20 crops, and then buy 3 cows. The entire mission can also be completed by paying 43 Horseshoes.
The fastest way to do this quest would be to plant the short crop such as Clover, which only takes 5 minutes to mature. The cows cost 765 coins, so it doesn't cost too much to complete this quest.