Solitaire game: Stack 'Em
Start with a shuffled deck.
The object is to stack from ace to king (or 2 to ace if preferred, as long as it's decided beforehand) in each of four stacks, one stack per suit.
You get two stacks of your own to work with (they start with no cards in them.). Cards are face-up. The rules for these two stacks are:
a) you can place a card on a stack only if it's of an equal or lower face value than the previous top card
b) you can take a card off of either stack at any time to place onto one of the four suit stacks.
You get 3 or fewer cards in your hand at any one time. You can take a card out of your hand and put it on a stack at any time.
(you may not take a card from any of the stacks and put it in your hand.)
Take a card from the top of the deck at any time and either place in your hand or onto any of the stacks if possible.
Do this process until you're stuck or you win.
Obviously, variants of this game can be created to make it easier, such as having three stacks and/or five cards in your hand, but I find that with a little bit of practice you can win with the above rules half or most of the time. I'd recommend the challenge.