Germs.io
I've been addicted to this game over the past few days when I have a spare moment I find myself getting hooked on this little game. Its similar to agar.io, but has some interesting twists to it. There's a few different rule options that are fun to play with. I've been flying around the map as one of my favorite strains, Cookie Jar (made it plural for fun and since you split up a lot). Check out this game if your bored or don't mind getting hooked on a simple yet fun game.