An unrealistic fantasy of most guys (nerds?) is to forge their own sword and wield it on the field of battle. Instructables user Mrballeng will show you how to forge your own Excalibur letter opener and wield it on the field of bill opening.
As you'll actually be hammering out a blade that's been heated up enough to be pliable, it's one of those projects you should be extra careful with. Fire and distractedness do not mix.
Once you get one of these made, you'll actually look forward to getting your post every day. You can even say to your wife/kid/husband/dog "fetch me my sword and my mail" a few times before they start rolling their eyes.
Excalibur Letter Opener [Instructables]