This one goes by many names. I've seen it in books as both Gaps and Spaces. Online, there are a few versions called Addition Solitaire. I've even seen a references to Deuces to Kings.
The idea is that all the cards are dealt in four rows of 13. Then the aces are removed to make gaps. You can move a card to a cap if it is the same suit and one higher than the card to the left of the gap. If the gap is in the leftmost column, then you can place any 2 card there. Naturally, nothing can go to the right of a king.
The idea is to arrange each row so it goes from 2 to king in the same suit. The last column in each row would be the remaining gap.
To help, you can click on the deck and reshuffle. This pulls in all cards that are not placed in their final 2-to-king same-suited position and deals them back randomly. The standard game lets you do this 3 times. If you change the setting to unlimited, then you can always win the game.
Check out my version of Gaps Solitaire and let me know what you think!