I recently tried a game called Leap Frog, a title that has been used a whole bunch of times. In this case, it's an In Hand game by Alexander Chen.
It consists of a small deck of cards. There are pictures of frogs from egg to full grown on the cards but all that actually matters is the numbers. There one 1 and three 2s,3s,4s,and 5s and two 6s. Really, you could make the deck out of a regular deck of playing cards if you wanted to.
Your goal is to get the cards in numeric order. It can be ascending or descending order. You don't use the whole deck, just seven of the cards. In the normal game, it's six random cards and the 1. In the challenge game, it's seven random cards period. You can swap a card with another card that it's value of spaces away. There's no time limit. Just keep going until you are done or you're sure it's impossible.
Now, here's the thing about the normal game. Having the 1 means you can always dink away at moving cards and any hand will always be solveable. It's only in the challenge version that you can have seven cards that are impossible to put in order.
A couple years ago, Shen made another In Hand game called Tumbling Thru Time that had a similar goal of putting numbered cards in order. In that game, when you used a card, you used it up so there were a limited number of moves in the game. I didn't enjoy Tumbling Thru Time and found it frustrating.
Leap Frog, with its unlimited moves, is a simpler and definitely easier game. Even in challenge version, it's not as frustrating. The only restriction that Leap Frog has that Tumbling Thru Time doesn't have is that you can't wrap around from one end to the other.
Alexander Shen designs tiny, little activities that basically take a cup of coffee to do. Which doesn't sound like much until you see how badly so many games like that are. Within their chosen niche, Shen is pretty brilliant. Leap Frog is a very simple game. I'd say it is the simplest In Hand game I've played but I've played Down. If you are looking for a real challenge, you won't find it here. If you are looking for a quick brain break, Leap Frog might work for you.
I think Shen's dice and more conventional card games are better than their In Hand games. But I do like having Leap Frog around.