Pumpkins would be one of my all time favorites. After halloween get all of the pumpkins you had, or your neighbors and friends have, and take them out to the country. Its pretty funny watching the back of the, or the whole thing blow up. We were using 12 gauge slugs to take care of them. I definately would recommend!

I've never shot a water melon with an '06
but i've shot a diller with an '06
And you think that water melon was a big explosion

Never shot a watermelon but a farmer I know gives away most of his leftover pumpkins after halloween. They come apart good after a 30-06 180 grain bullet.

If you've got a safe place to try, check this combination out: glue one of those small exploding targets to a can of spray paint. Be sure you are 100 yards away. If you can hit the exploding target dead on and go through the can of paint, you'll get a 10 foot fireball.

A more environmentally friendly explosion is a hit on a block of ice. When the temp gets below freezing I fill 2 liter Pepsi bottles and put them outside overnight. When I hit them with a .308 I get a good spray, and I can usually get 2 or 3 hits on each bottle.

The spray paint idea sounds pretty enviromentally friendly. I find those big starch spray cans much better though.

I once filled up a propane tank with air out of a compressor and shot from 300 yrds with a 30-06 and you should have heard it and seen it it was incredible