My high school best friend got me hooked into this: Jigzone, a free online jigsaw puzzle website where you can solve puzzles ranging from the easy 6-piece to the difficult and dizzying 247-piece triangle-shaped puzzle.
As mentioned on its website, Jigzone is truly a jigsaw paradise as it has got thousands of puzzles to choose from. Every day, the jigsaw website features a puzzle of the day. If you don't like the day's featured puzzle, you can view the puzzles from their gallery, which are categorized according to their theme.
Registration to the jigsaw puzzle site is not required, as you can just play instantly. However, it's still best to sign up for a free account so you can compete with your friends and share your "solve times" with them. But the best part of having a account is on this jigsaw website is that you can upload your pictures, and turn them into your own jigsaw puzzles, which you can post on your website, or send as a puzzle postcard to your loved ones. Here's a picture jigsaw puzzle I made with my husband's baby picture:
Like real jigsaw puzzles, Jigzone can be truly addicting. I'll bet once you've tried a jigsaw, you'll never be content with solving just one puzzle.