Well if you have a kid - buy it. Some of the puzzles - questionable, but most of them are great fun. If you want best of the best buy The Moscow Puzzles: 359 Mathematical Recreations (Dover Recreational Math).
Fantastic book starting with really simple teasers and slowly progressing to challenge the puzzle enthusiasts. A classic collection that every generation must try. It reminds me of the book my parents got for me when I was a kid. The difficulty level is beginning to intermediate - no need for differential calculus. Bought for my 10 year old son but enjoyed by both: the boy and myself.
Martin Gardner produces a mixture of jokes, puzzles and teasers. It is suitable for a range of ages. Children from 6 up will enjoy the jokes, while some of the puzzles need rather more skill and parental guidance. Definitely recommended.