Helps, Administration, Serving, Teaching, Encouraging, Contributing, Leadership, Mercy, Marriage, and Celibacy are all natural gifts.
By this I mean that they are not unique to Christianity. Many unbelievers, for example, have a gift for administration. The uniqueness of these gifts for the Christian lies in the empowering of the Holy Spirit.
Wayne Grudem, although I pretty much diverge from his interpretation after this, offers a good definition of Spiritual Gifts.
A Spiritual Gift is any ability that is empowered by the Holy Spirit and used in any ministry of the Church. Grudem, W. Systematic Theology (Zondervan, IVP Leicester, Grand Rapids, 1994).So all gifts are essentially miraculous in this definition. They are all empowered by the Spirit to accomplish the purposes of God in the furtherance of His kingdom on this earth. All Christians have a Spiritual gift. All Christians are empowered by the Spirit in their exercising of that gift.
Whether it be something undramatic, such as Administration, it is still a gift from God that He is using that Christian to accomplish.
It should be noted that these gifts are only considered Spiritual, when they are being employed in the power of the Spirit, and when they are advancing the Kingdom of Christ. This does not mean that (we'll stay with administration) a person at work does not use a Spiritual Gift on the job. What it means is this, A person at work, who is gifted with administration and views his job as a vocation where he has been placed by God, should administrate in the power of the Spirit for the advancement of Christ's kingdom.
Now there are many other gifts that are not listed in Scripture. Your vocation is a gift. Whether you are a Janitor or a Lawyer, God has placed you in your position in order for you to be the best Lawyer or Janitor you can be, and He has gifted you and empowered you in this way, for you to be a Janitor or Lawyer.
You can tell when you are operating in the power of the Spirit by your attitude, your performance, and whether not God is the One who is glorified by your work.
Let the reign of terror from the Centuri0n begin.