Scratch

that depends on your skill level really. Obviously, the more skill you have the more options you will have.

So assuming you have just started here's an idea: make a game that involves a mouse or something running away from a cat or something. You will decide how that mouse moves and how the cat follows the mouse (you should probably just make the cat point at the mouse and move forward). If the cat touches the mouse you lose.

If you manage to avoid the cat for a set period of time you move onto the next level. The higher the level the faster the mouse goes but will also increase the number of cats.

You may also want to include score.

What about a Themed Game or Animation Perhaps?

As you're a New Scratcher, I'll give you simple ideas.
Now,
take this cat.
Now, take this mouse and save the image as "mouse" without the quotes.
Open Scratch and you will have the cat. Add the mouse as a character, now add this script to the mouse.

when gf clicked
say [Move me with the arrow keys, P1.] for (2) secs
broadcast [cat_message v]

Now give the Scratch Cat this script:

when I receive [cat_message v]
say [Control me with WASD, P2.] for (2) secs

Now, do this script on the mouse:

when key [up arrow v] pressed
change y by (10)
when key [down arrow v] pressed
change y by (-10)

Do the same with left and right arrow, except with the steps button. Add the - on the left arrow trigger.
Do the same with the cat but choose the letter w for up, s for down, a for left and d for right.
Now, make a variable called P1 score (and P2 score, set it to zero too). Set it to 0 when flag clicked, then make a thing underneath the set variable P1 score to 0 that says if not touching cat and timer > 100 say P1 wins this round and reset timer then add 1 point with the variable tags. Do the same with cat, except say, if touching mouse, say P2 wins this round and reset timer then add 1 to P2 score. On Stage, say that when green flag clicked P1/P2 score will appear.
Save the game. Name it Partner Chase. Now share it with any description you like. -eveadelekitty