If you ever wanted to use your electric guitar to jam along with a group of friends playing acoustic outside, then this is the project for you.
It's easy to make, and only takes about an hour. I made my circuit based on the following instructions, but modified some component values based on what I had on hand. http://makezine.com/projects/make-09/the-5-cracker-box-amp/ It sounds great and with the gain all the way up, is surprisingly very loud. The sound is very distorted, both leads and powerchords blend well with acoustic guitar. Dialing the gain back provides a usable tone, but tends to sound a little bit lo-fi and cheap (well, it does only cost around $10) in a bad way. It's a great project to get started in electronics, and is actually practical.