Employees, even those who are reasonably happy, are only happy because of a series of things, most of which the employer has control over. It takes time, effort and thought into making sure that employees are happy (and as productive) as they can be. There isn’t any one thing you can do to guarantee a happy employee, but here are a few ideas that will help boost employee morale, leading to happier employees.

1. Thank the employee. It is simple and when  it is sincere, makes the person feel appreciated. Thank him/her for a job well done, even if it is only the effort for trying.
2. Give a LinkedIn recommendation following a job well done. This not only thanks the person for a particular task/job, but does so publicly to that persons professional network.  (This works for people who may not be your employees too – colleagues in other departments, partners, etc.)
3. Hand out “Get out of a meeting free” card. Everyone gets busy and sometimes the meetings are at really bad times. While each meeting should be valuable, make sure your team knows that you value their judgment on when they can better use their time.
4. Let employees reward each other. Second Life goes a step further and allocates a financial bonus that employees can designate to another employee. Again, it encourages a team environment where team mates want to work together and be recognized.
5. Reward employees with something fun to do. It can be something huge or something very small – but it reminds them (and you) that their life is not defined by work.
6. Make a game out of tedious (but necessary) tasks. This can be anything from speed contests to randomly choosing a winner (I’ve hidden a sticker in these envelopes to stuff – the person who finds it wins). It makes the task far easier to do if it can be made fun.
7. Help them with their pet projects. If an employee is raising money for their favorite charity, do what you can to help them (by donating money or helping in another way). It will show that person that you value them not only as a worker-bee, but also as a person.
8. Create a time during the week in which the employees are encouraged to play a game (cards, basketball, etc.). This built in break time can help them focus on work and build a team spirit.
9. During a lunch hour, bring in a movie for the team to watch together – people can take turns picking the movie and watch it over 2 or 3 days.
10. Ask the employee what you can do to recognize them (and do it). Everyone is motivated differently – some by money, others by recognition, others by new challenges. You won’t know what will work unless you ask.

Post in the comments a few other ideas that you have either seen work (or seen fail).