Back in the day, musicians used candles as metronomes to keep time. Now, you can too, cause in the music industry, it's better to burn out than to fade away.
Obviously, this may not be the best metronome around, but DIY is how to do it if you can't afford a good one. Even if you're not in a band, you can still make this rocking candle apparatus to show to your friends.
Plus, it's way cooler to have one of these burning when the power goes out, instead of flashlights.