Living in an apartment can be crappy for practicing your guitar. If you don't buy some expensive gear to be able to quietly play with headphones, your amps and electric guitars can become just furniture. But here's a cool idea from DelSonix, a passive speaker for your electric guitar so you can hear what you're playing. It's great for the bass!

Check out these demos, and you can hear a big difference in sound from the speaker clamped to the headstock. No, you won't get distortion sounds or anything, you'll just be able to hear the guitar better, so you can pay attention to what you're playing.

This would be great for practicing exercises, so no one else in your place will have to be driven nuts with scales at high volume, haha.