For ages I have loved doing Kakuro puzzles. I like numbers. It is funny to me how all of a sudden Sudoku became all the rage yet it has been around for ages in puzzle books. In those same books they would have Cross Sums also know as Kakuro. Anyway, if you have never tried Kakuro give it a shot. It helps keep the mind quick with numbers. I highly recommend it for kids because it not only helps with getting faster with addition but it involves logic as well.
My daughter and I have spent the better part of the morning having a Kakuro contest. Needless to say I am whipping her however she doesn't seem to mind.
These days I play on Facebook but I used to have a big book full of them. Recently, I haven't been able to find any of the puzzle books in the stores so playing online will suffice.