This is not the coolest knife block I've built, but it was the first and it's the one Apartment Therapy linked to, so it's the one you're finding on Google. Check out the bamboo skewer knife block I built out of red oak as a wedding present. I also made a knife block out of reclaimed pallet lumber recently, but for some reason haven't posted it yet.

I recently saw the Martin Robitsch Schaschlik, which is a pretty clever little gadget. It's basically what you see above: a wood box. It also has what are basically little bamboo skewers all through the inside. That way you have a knife block that you can put knives in however. It also costs a whopping $125 though. I started building my own today, and so far it's cost about $15. It's made out of some old pine I just had laying around, cut and sanded. Then I spent some actual money on stain/finish and some lead weights to put in the back. Really the weighted back is one of my favorite things about it. You know how most knife blocks have a little buttress on the front so they don't tip forward? Mine doesn't because it's just that awesome.