This year, I learned a new tool named "Bendaroos." It is basically some waxed sticks which are easy to bend, shaped, attached and removed on wall or window without making a damage.
If you see my friend's art master piece, you will know What I made is definitely just simle craft.
Note: Here is my REAL time consumeing project - making my soon-to-be 4 year-old son KK sit down and wrote his Valentine's cards for his classmates!