I usually go on jigzone.com and do puzzles, but have been buying a few later too. I just finished a 1000 piece puzzle. The "buried blueprints" puzzles are really hard!!
During one snowstorm I helped a friend put togeether a puzzle that was nothing but pencils lined up. I'm talking just plain ol yellow pencils! That friend is a puzzle nut though. She put like 10 pieces in for every one or two I did! Her father once did a puzzler that had no picture. It was one solid shade of green!