One of the biggest keys to a happy retirement is getting to do what you really want. After all, you’ve worked a long time to get to the point where you have full control over how you spend your time. If your ultimate retirement involves a lot of R&R, and you’ve got the resources to do it, then by all means go for it. On the other hand, you may be one of the growing number of people who find they still want to engage in some gainful and rewarding work during their advanced years. If you fall into that category, there are any number of positions that can be fun and challenging while putting some added dough in your accounts.