This uses no redstone, and you can do it in survival (although the donkey might be hard to find)
Materials:
Donkey with a chest saddle
Lots of random blocks or junk
Fence (at least 11)
A lead

Method:
1. Place fence at least 11 blocks high.
2. Place fence at least 3 blocks horizontally in any direction.
3. Get the Donkey and fill it's chest with all the random items
4. Use a lead to connect the donkey to the horizontal block furthest from the tower
5. After the Donkey has risen up, feel free to pummel it with anything until it dies, dropping an array of random items for you to reclaim.
6. Repeat steps 3-5

This is great fun with friends, especially in a Minecraft party (Note: This is much easier in Creative)
I hope this post will give you hours of fun (the majority of which will be spent setting this up.)
Enjoy! Feel free to leave a diamond, give this tutorial a heart, and sub for more!