|When companies put on a little contest, only to ignore the little rules, it is a sign of management with little skills. The larger question in your situation is whether this type of behavior is extremely rare, or whether it is yet another example of management's belief that commitments also mean little.|
If the delay in presenting you with your prize is an aberration, you can certainly go back to your manager and mention that you are suffering from prize deprivation and would like your just reward. Be sure to pick a time when he is not extremely busy.
However, if it is typical of your manager to conveniently forget about your prize, you can still approach him and tell him that you would like the prize, express your concern over what happened, and then ask him what he would do if he were in your situation. Then follow his advice. You always have the option of approaching his manager, but the real question is whether this issue is worth it.
Many companies have found that contests can be a great source of improved satisfaction, motivation, and even productivity. However, if handled with the least bit of inequity, they can be a greater source of distrust, distress, and dissatisfaction. And, this latter outcome is virtually guaranteed when the manager is no prize.