I remember I used to love the fruit of the loom commercials when I was a kid, featuring those guys in green grape, purple grape, apple and leaf costumes. Similar costumes are available, and are not restricted to those particular fruits. Banana, strawberry, blueberry, orange, pumpkin (a natural for Halloween), lemon, lime, and others can be purchased online in child and adult sizes. Fun, goofy and colorful.
Fruit costumes pictured:
Left: Fruit (Green Grapes) Adult Halloween Costume Size Standard
Middle: Girls Infant Toddler Strawberry Halloween Costume
Right: Apple with Worm Adult, Red, One Size Fits Most
Some of these costumes require you to wear a bodysuit. Make sure to check whether it is included or not. Also think of what kind of footwear you will be wearing. The wrong type of shoes or boots can really have a negative impact on the overall look of a costume.