Pandaora's Box is really nice. It's made with cheap, easily accessible materials, and is easily transferable to a new card box if needed. You can also still fit a full deck of cards inside the gimmicked box. Although you can't fully show both sides, you can give a quick convincer that it is completely normal.

I'd recommend Gary Plants card box too. Beautifully made.

"Watch, Look and Listen" from The Close Up Magic of Frank Garcia Part 2 is excellent. It's an idea by Ray Grismer with finishing touches by Peter Kane.

Before I started magic 'properly', I used to do the effect after seeing it in a beginners magic trick book.
If the following items mean anything to anyone, you'll know it still works pretty well!!!

Matchbox
Rubber band
Coin

;-)
Kneill.