My sister and I found a snowcone maker at Target last summer. All it does is crush ice, which you can do in a blender, but this gadget does it evenly so you don't get any big lumps in the mix. The silicone cones make it extra cute...we bought extras in solid colors since we usually have lots of guests.
Rather than pouring super sugary syrups over the ice we just use fruit juice. The kids still think they are a big treat! The other thing you can do, if you plan ahead a little, is freeze juices into cubes so that the ice itself is already flavored.