Some novel garage speakers using plastic gas cans and a 2-way speaker kit. Standard 5L/1.25gal gas cans fit a 2-way 6.5" woofer/tweeter kit perfectly. As an added bonus, the pour spout serves to release pressure in the speaker can. You can get everything you need for ~$69 from Amazon and/or Home Depot.
Step 1: Materials
If you don't have anything to plug the speakers into, here's my approximate setup:
Step 2: Electrical Dry-Run
I wired up the speaker kit components before delving into the enclosure. You might want to do the same to see how everything will fit together. The Pyle kit comes with everything you'll need except the terminals, including the +/- wire. Just wire the woofer, tweeter, and terminals to the corresponding +/- pins on the crossover. Test it out with the amp/stereo you'll be using. You may initially feel that the speaker isn't loud enough, depending on your amp of choice, but I promise when you get everything in the can and two of them side-by-side, it will be more than satisfactory.
Step 3: Cut holes
We need to cut holes in the can for the woofer and tweeter. The Pyle kit comes with a template for the woofer cutout which I found to be completely inaccurate. What I recommend is to cut out the template circle, place it centered on the flat side of the gas can, and draw a circle about a 1/2 cm outside the circle so that your final diameter is a full centimeter wider than the template.
For the tweeter hole, place the tweeter's flush-mount rim on the corner notch and trace a rough circle. The Pyle kit's tweeters break into three pieces (and a spring). They can sometimes be stubborn, but just go ahead and yank it apart.
For both circles, I drilled a couple adjacent holes on the inside of the circle to give me enough space to get the saw in and cut all the way around. I used a cheap metal hack saw which worked rather well. If you have a reciprocating saw or a jigsaw, kudos to you - you may get this done faster. The woofer hole should be the right size and will need little extra attention. For the tweeter hole you'll probably want to test-fit the flush-mount flange repeatedly as you refine the hole, cutting it wider as needed.
Step 4: Terminal ports and installation
You can have the terminal ports stick off in any direction you like. You can really just have the +/- wires hang out the pour spout, but I think it looks really nice with the terminal pins on the side. On the first speaker I just drilled adjacent holes and stuck the terminal pins through. Attach the nut and locking washers to the other side, sandwiching the +/- wires between the locking washers on the corresponding terminal.
About now we can start sticking components in the can. Stick the crossover toward the back of the bottom of the can using one of the round double-sided sticky pads that came with the kit. Snap the tweeter and backing (with spring) into the flush-mount rim from the back. Sometimes the tweeter may tend to pop in or the rim out of the hole we drilled, so it won't hurt anything to duct-tape it to the inside of the can.
Lastly, we cram all of the loose/extra wire into the can and mount the woofer. For the woofer attachment holes, place the speaker and black rim where you want them, then poke an awl or drill bit through the holes to mark them on the can. You may drill them out if you like but I found I could just hand-screw the speaker on without pilot holes. The can's plastic is sturdy enough that you don't need anything to back the screws, but you may try the metal clips that come in the Pyle kit if you feel so inclined.
Step 5: Finishing up
Pop on the speaker grill and plug it in! If you didn't have an audio system to use the speakers with beforehand, setting up the amp and speaker wire (and banana plugs) should be self-explanatory. Definitely Google how to straight-mount the banana plugs on the speaker wire.
Repeat for the second speaker. I used the other side of the gas can so that they make a nice symmetrical set. For the second speaker, I tried to use the little black mounting plates that came with the terminals to make them a little sturdier. I recommend it, just make sure the pilot holes are perfectly straight or the front and back plates will not line up.
Now don't expect incredible audiophile sound out of these, but for the untrained ear like mine, they produce great sound. If you hear any rattling, just double-check that everything is securely attached. The terminal plugs will rattle a bit if not screwed all the way down. You can also optionally stuff the can with normal polyfill through the pour spout to round out the sound a bit.