Regular exercise can make people happier, more energetic and improve job skills; thus, it should be a no-brainer for you to encourage your workers to work out regularly. One way to do so is to pay for or supplement the cost of gym memberships. Many gyms are willing to negotiate package deals if you have your employees join at group rates; in fact, such deals may end up costing you very little, or even nothing at all.
Worried workers are bad for business, particularly those with young children. Assuage those worries by offering assistance with the costs of daycare for those workers with children; your employees will love you, be more relaxed and view you as charitable. What's more, you'll be doing your part to help raise better citizens for the next generation of people and workers.
Finally, encourage your employees to fraternize by regularly hosting lunches in the office. This low cost benefit may lead to workers becoming friendlier, which can lead to bonds that cause a better work environment and a togetherness that will come through in the work your employees do.