Here are quite a few posts for you to check out:
• Best Adjustable Coffee Tables
• Good Questions: Any Adjustable Coffee Table Resources?
• Good Questions: Convertible Coffee/Dining Tables?
• Adjustable Coffee table Mechanism
• The Hydra Table
• Ligne Roset Knockoff?
• Matthiessen Tray Table
• Flip Table by Flipfurniture
• The Mascotte Table
Note: Include a picture and your question gets posted first
Image: Yo-Yo by Ligne Roset