Went out to the desert with a friend yesterday and had a great time. We spent about 2 hours or more on top of a small mesa, shooting at a larger hill about 150 yards distant, as a backdrop. There was a 25 foot, fairly steep dropoff in front of us. We were rolling a oranges and lemons down the hill and shooting at them.
They picked up speed fast and were fun targets...Plus, 100% biodegradable. Some rounds, like 223 and 22 lr's went right through the fruit with tiny holes in the front and penny sized holes on the far side. A good hit with a 9, 40, or 45 will blow the offending fruit into pieces.
In the past, this same friend and I used to use pumpkins at targets. The hydrostatic pressure blows the stems off them. More then one pumpkins had it's stem tossed 20+ feet straight up with 7.62x39mm HP's.
Small balloons also make good targets when tied to a shrub, with the wind blowing are challenging.