The 15 game

In the first game, there are nine numbers, 1 2 3 4 5 6 7 8 9. You and your opponent take turns, taking one number each time. You can only take a number once, so if your opponent has taken a number, you can't take it also (and neither can your opponent, again). The winner is the first person whose numbers total 15.

Here's an example:

                                    You         Your opponent
        1 2 3 4 5 6 7 8 9

    You take 1

          2 3 4 5 6 7 8 9           1

    Opponent takes 8

          2 3 4 5 6 7   9           1           8

    You take 5

          2 3 4   6 7   9           1,5         8

    Opponent takes 4

          2 3     6 7   9           1,5         8,4

    You take 9, and win!

          2 3     6 7               1,5,9       8,4