I've lately found this cool online game called agar.io
In this game you start as a tiny ball kind of cell and you need to grow up by eating other balls or other smaller players while you avoid other bigger players that wants to eat you.
http://play.pokemonshowdown.com
Browser-based pokemon battle simulator, you can custom create your own team and choose each pokemon's traits from their movesets down to their exact EVs and IVs. There is also an ELO rating system and different competitive tiers for each pokemon to make battles more fair