Hand-held Skate Sharpeners
A company called Revol Hockey makes a great portable hand-held skate sharpener called the Raptor.
The Raptor uses ultra hard ceramics that renew your edges by straightening the small burr that was created by using your skates. This produces a new sharp skate edge in much the same way as self-sharpening knives. All you need is two strokes down your blade to sharpen your skates.