You probably can find books or magazines containing word jumble puzzles, but you may prefer to create the puzzles yourself. Creating the puzzles yourself has the advantage that you can customize the puzzle for different occasions, pick words suited to your child's reading level, and tailor the puzzles to your requirements (for example bu avoiding hard_to_find diagonal words in puzzles aimed at younger children). Creating puzzles yourself is possible using nothing more than a pen and paper, but you'll find it incredibly time consuming _ so a better alternative may be to use your computer and some word jumble maker software _ that way you can simply enter a list of words, and the computer will generate the puzzle automatically.
The more involved games come at a cost but it is usually nominal, a few dollars at the most and you have a unique game to keep the guests entertained. The best board games to be found are usually question and answer games, where the guests partner up and try to answer questions about the couple or each other for points or spaces on the printed out board. Many games are able to be customized so that you can enter specific questions about guests or the expectant parents to print out.