Thinking is a service we provide but it's more commonly known as troubleshooting. The most difficult part of solving most problems is identifying exactly what the problem is - "It doesn't work" - isn't good enough.
These are links to games that are outside the realm of the "normal" computer game. One of the reasons that we like games is that they challenge us to think in ways that are different from the way we think every day. This can not only be fun but it also may improve our ability to think. Whether the preceding statement is true or not, the games sites linked here can provide a thinking challenge.