Take boredom to task and strengthen your operational abilities (multiplication, division, addition, and subtraction) in math.  In the game of kenken you must have the same all of the numbers in each row and column.  Start with a 3 x 3 puzzle.  Inside of the larger square there are shapes with numbers and operation signs next to them.  For example, if it say 2 - I must put two numbers inside that shape that subtract to make 2.  If you are doing the 3 x 3 square, only 3 and 1 will work.  These are challenging and maybe a wee bit addictive but most importantly they are great practice for your personal number calculator (your brain)...lol.  Have fun!