Ikea Hackers is a website that showcases and encourages the hacking/modification/repurposing of Ikea products.
The Knuff Table is a pretty clever Ikea Hack. It uses nested Knuff wood magazine holders as the tabletop. The nested boxes allow the tabletop shape to be adjustable, and the open ends can be used as a storage space.
The Frosta X is part of a subcategory of Ikea Hacking that is based upon the Frosta stool. I really like the Ikea style instructions.

Lova Elf Wings
A bit more on the whimsical side, the Lova Elf Wings are made from a children’s canopy, some curtains, a blanket, and a placemat. I’m not a huge fan of this as a concept, my tastes lean more towards the functional, but I think its a very creative adaptation of Ikea Products. Its a great example of someone taking something, and turning it into something the original designers never dreamed of.