I made this slip cover for Miss M's Ikea 'Mammut' kiddie chair - here's how I did it!
The project takes about a leisurely 2 hours all up (less per chair if you make more than one at a time of course) and I would say is pretty easy - just straight sewing, careful pinning and a glass of wine.
A great way to refresh the style of your playroom, or add more handy storage at the desk!
You could also go a bit nuts and make other accessories to match...