Chess - play the classical game against a smart algorithm or a friend. Lots of setup options
Insights from the gaming industry
Digital Pets Games
A digital pet (also known as a virtual pet, artificial pet, or pet-raising simulation) is a type of artificial human companion. They are usually kept for companionship or enjoyment. People may keep a digital pet in lieu of a real pet. Cyberpet and Tamagotchi were some of the first digital pets.
Digital pets are distinct in that they have no concrete physical form other than the hardware they run on. Interaction with virtual pets may or may not be goal oriented. If it is, then the user must keep it alive as long as possible and often help it to grow into higher forms. Keeping the pet alive and growing often requires 'feeding', grooming and playing with the pet. If the interaction is not goal oriented, the user can explore the character of the pet and enjoy the feeling of building a relationship with it.
Digital pets can be "simulations of real animals, as in the Petz series" or "fantasy ones like the Tamagotchi or Digimon series'". Unlike biological simulations, the pet does not usually reproduce.
Virtual pet sites are usually free to play and accessible to all who sign up. They can be accessed through web browsers and often include a virtual community, such as Neopia in Neopets. In these worlds, a user can play games to earn virtual money which is usually spent on items and food for pets. One large branch of virtual pet games are sim horse games.
Some sites adopt out pets to put on a webpage and use for role-playing in chat rooms. They often require the adoptee to have a page ready for their pet. Sometimes they have a setup for breeding one's pets and then adopting them out.
Most sites use quests in order for users to make points and receive items. Some quests can give stat points to the user's pets for when they are battling. Such sites that use quests for a primary foundation on the site are Neopets and Marapets. These sites, and their clones, have a single non-dynamic image for each pet and its various colors, leading to a lot of similarity in the pets.
There are also "simulation sites" where the webpage attempts to simulate a real-life discipline, such as horse dressage or pedigree dog showing. Often these sites will also have a breeding aspect, including genetics and markings. Other simulation sites focus mostly on the markings. Some have done away with the showing aspect and created a great fantasy or comedic website, based around a nonexistent discipline or creature. An example of this is Woolly Hooves, a simulation game where the player gets his/her very own elemental llama, and goes on to hike, explore and complete less single-objective quests than some sites in a bizarre yet endearing world. A few more websites with a similar genre include Kingdom Of Knuffel, Mweor, Khimeros, Xanje, Aywas, Wajas, Tygras, The Dragon Empire and many more