Perfect Ice Spheres
How badly do you want a perfect ice sphere in your drink? You can't make them in a tray; a special machine is required. Some people pay $8 each (plus shipping) to have some spheres overnighted in dry ice. If you're the do-it-yourself type, or just want to have something extraordinary for your home bar, then you might be in the market for a sphere-maker:

Crazy expensive (starting at $200 for the smallest sphere size), but undeniably cool and fun to watch in operation. The manufacturer also offers molds to create ice diamonds and sports balls. Check out the video at Japan Trend Shop.