A head-to-head maze race. Escape a maze as fast as you can, text a friend the same maze, and see who's quicker. Same maze, same clock — winner takes the bragging rights.
Escape the same maze your friend just ran and try to beat their time — then send it back and make them chase yours. A fast head-to-head race with a rival built in. No accounts, no downloads: just a link and some bragging rights.